1057 lines
38 KiB
C++
1057 lines
38 KiB
C++
/* file tokenizer.hpp
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*
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* author: Roland Conybeare, Jul 2024
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*/
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#pragma once
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#include "token.hpp"
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#include "input_state.hpp"
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#include "span.hpp"
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#include "scan_result.hpp"
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#include "xo/indentlog/scope.hpp"
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#include "xo/indentlog/print/ppdetail_atomic.hpp"
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#include <cassert>
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namespace xo {
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namespace scm {
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/** @class tokenizer
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* @brief Parse a Schematika character stream into lexical tokens
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*
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* Use:
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*
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* @code
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* // see xo-tokenizer/example/tokenrepl/tokenrepl.cpp
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* // for exact working code
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*
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* using tokenizer_type = tokenizer<char>;
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* using span_type = tokenizer_type::span_type;
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*
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* tokenizer_type tkz;
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* span_type input = ...;
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*
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* while (!input.empty()) {
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* auto [tk, consumed, error] = tkz.scan(input);
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*
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* if (tk.is_valid()) {
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* // do something with tk
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* } else if (error.is_error()) {
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* error.report(cout);
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* break;
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* }
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*
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* input = tkz.consume(consumed, input);
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* }
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*
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* if endofinput {
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* auto [tk, consumed, error] = tzk.notify_eof()
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*
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* // do something with (final) tk if tk.is_valid()
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* }
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*
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* @endcode
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*
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* See tokentype.hpp for token types
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**/
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template <typename CharT>
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class tokenizer {
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public:
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using token_type = token<CharT>;
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using error_type = tokenizer_error<CharT>;
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using span_type = span<const CharT>;
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using input_state_type = input_state<CharT>;
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using result_type = scan_result<CharT>;
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public:
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/** @defgroup tokenizer-ctors tokenizer constructors **/
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///@{
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tokenizer(bool debug_flag = false);
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///@}
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/** @defgroup tokenizer-access-methods tokenizer access methods **/
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///@{
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#pragma GCC diagnostic push
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#ifndef __APPLE__
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#pragma GCC diagnostic ignored "-Wchanges-meaning"
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#endif
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const input_state<CharT> & input_state() const { return input_state_; }
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#pragma GCC diagnostic pop
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///@}
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/** @defgroup tokenizer-general-methods tokenizer methods **/
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///@{
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/** identifies punctuation chars.
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* These are chars that are not permitted to appear within
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* a symbol token. Instead they force completion of
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* a preceding token, and start a new token with themselves
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**/
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static bool is_1char_punctuation(CharT ch);
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/** more-relazed version of is_1char_punctuation.
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* Chars that are not permitted to appear within a symbol token,
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* but may form token combined with next character
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**/
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static bool is_2char_punctuation(CharT ch);
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/** assemble token from text @p token_text.
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* @p initial_whitespace Amount of whitespace input being consumed from input.
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* @p token_text subset of input_line representing a single token.
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* @p input_state input state containing input_line
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*
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* retval.consumed will represent some possibly-empty prefix of @p input
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**/
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static result_type assemble_token(std::size_t initial_whitespace,
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const span_type & token_text,
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input_state_type & input_state);
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/** degenerate version of assemble_token() on reaching end-of-file **/
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static result_type assemble_final_token(const span_type & token_text,
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const input_state_type & input_state);
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/** true if tokenizer contains stored prefix of
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* possibly-incomplete token
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**/
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bool has_prefix() const { return !prefix_.empty(); }
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/** scan for next input token, given @p input.
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* Note:
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* - tokenizer can consume input (e.g. whitespace)
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* without completing a token
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* - input will remember the extent of the last line of input
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* for which parsing has begun, but not completed.
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* It's required that at least that portion of the input span
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* remain valid across scan(), scan2() calls
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*
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* @return {parsed token, consumed span}
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**/
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result_type scan(const span_type & input,
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bool eof_flag);
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/** discard current line after error. Just cleans up error-reporting state **/
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void discard_current_line();
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///@}
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private:
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/** @defgroup tokenizer-instance-vars tokenizer instance variables **/
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///@{
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/** track input state (line#,pos,..) for error messages.
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* There's an ordering problem here:
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* 1. input_state_.skip_leading_whitespace() advances current line automagically
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* when it sees \n
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* 2. need to capture value of @ref input_state_ _before_ newline
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* 3. but neeed newline to end token
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* Also recall input_state_type needed for reporting errors.
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**/
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input_state_type input_state_;
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/** Accumulate partial token here.
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* This will happen if input sent to @ref tokenizer::scan
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* ends without whitespace such that last available token's extent is not determined
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**/
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std::string prefix_;
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///@}
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}; /*tokenizer*/
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template <typename CharT>
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tokenizer<CharT>::tokenizer(bool debug_flag)
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: input_state_{debug_flag}
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{}
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template <typename CharT>
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bool
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tokenizer<CharT>::is_1char_punctuation(CharT ch) {
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switch(ch) {
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case '(':
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return true;
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case ')':
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return true;
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case '[':
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return true;
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case ']':
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return true;
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case '{':
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return true;
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case '}':
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return true;
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case '<':
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/* can't be 1char punctuation -- can begin lessequal token */
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return false;
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case '>':
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/* can't be 1char punctuation -- can begin greatequal token,
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* and appears in tk_yields token
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*/
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return false;
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case ',':
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return true;
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case ';':
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return true;
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case ':':
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/* can't be 1char punctuation -- can begin assignment token */
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return false;
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case '=':
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/* can't be 1char punctuation -- can begin comparison token '==' */
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return false;
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case '!':
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/* can't be 1char punctuation -- can begin comparison token '!=' */
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return false;
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case '-':
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/* can't be punctuation
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* - can appear inside f64 token: e.g. 1.23e-9.
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* - begins tk_yields token: ->
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*/
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return false;
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case '+':
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/* can't be punctuation -- can appear inside f64 token: e.g. 1.23e+4 */
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return false;
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case '*':
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/* not punctuation -- allowed in symbol */
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return false;
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case '/':
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/* not punctuation -- for symmetry with +,- */
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return false;
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case '.':
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/* can't be punctuation -- can appear inside f64 token: e.g. 1.23 */
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return false;
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}
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return false;
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}
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template <typename CharT>
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bool
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tokenizer<CharT>::is_2char_punctuation(CharT ch) {
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/* can't put '-' here, because of the way it appears in numeric literals
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* characters here may not appear in symbol names
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*/
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switch(ch) {
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case '<':
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/* can begin <= */
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return true;
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case '>':
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/* can begin >= */
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return true;
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case ':':
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/* can begin := */
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return true;
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case '=':
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/* can begin == */
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return true;
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case '!':
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/* can begin != */
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return true;
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}
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return false;
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}
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template <typename CharT>
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auto
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tokenizer<CharT>::assemble_token(std::size_t initial_whitespace,
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const span_type & token_text,
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input_state_type & input_state_ref) -> result_type
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{
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/* literal|pretty|streamlined */
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log_config::style = function_style::streamlined;
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scope log(XO_DEBUG(input_state_ref.debug_flag()));
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log && log(xtag("token_text", token_text),
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xtag("initial_whitespace", initial_whitespace),
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xtag("input_state", input_state_ref));
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tokentype tk_type = tokentype::tk_invalid;
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std::string tk_text;
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const CharT * tk_start = token_text.lo();
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const CharT * tk_end = token_text.hi();
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const CharT * ix = tk_start;
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/* switch here applies to the first character in a token */
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switch (*ix) {
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case '-':
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case '+':
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if (token_text.size() == 1) {
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/* standalone '+' or '-' */
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if (*ix == '+')
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tk_type = tokentype::tk_plus;
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else if(*ix == '-')
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tk_type = tokentype::tk_minus;
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}
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/** fall through to numeric literal code below **/
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[[fallthrough]];
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case '.':
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case '0':
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case '1':
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case '2':
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case '3':
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case '4':
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case '5':
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case '6':
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case '7':
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case '8':
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case '9':
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{
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/* examples of valid floating-point numbers:
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* .0
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* 1e0
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* 1e
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* 0.
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* +1e0
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* -1e0
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* +1E+2
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* -1E+2
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* -0.123e-10
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* non-examples:
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* .
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* -
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* +
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* e0
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* .e0
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* -.e-0
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* +.e+0
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*
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* in particular: to be recognized as a number,
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* must contain at least one digit
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*/
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log && log("possible number-token");
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/* true if initial sign -/+ encountered */
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bool sign_flag = false;
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/* true if '.' encountered */
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bool period_flag = false;
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/* true if 'e' | 'E' encountered.
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*/
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bool exponent_flag = false;
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/* true when sign '-' | '+' precedes exponenct digits */
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bool exponent_sign_flag = false;
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/* true when at least one digit follows exponent marker */
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bool exponent_digit_flag = false;
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/* true if at least one digit encountered */
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bool number_flag = false;
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log && log(xtag("*ix", *ix),
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xtag("tk.length", token_text.size()));
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if (log && (ix + 1 < tk_end))
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log(xtag("*(ix+1)", *(ix + 1)));
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if ((*ix == '-') && (ix + 2 == token_text.hi()) && (*(ix + 1) == '>')) {
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/* composing exactly '->' */
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tk_type = tokentype::tk_yields;
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} else {
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/* token (if valid) will be one of: {tk_i64, tk_f64, tk_dot}: */
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for (; ix != token_text.hi(); ++ix) {
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if ((*ix == '-') || (*ix == '+')) {
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/* sign allowed:
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* 1. before period and before first digit
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* 2. after exponent
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*/
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if (!period_flag && !number_flag && !sign_flag) {
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sign_flag = true;
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} else if (exponent_flag && !exponent_digit_flag) {
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exponent_sign_flag = true;
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} else {
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return result_type::make_error_consume_current_line
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(__FUNCTION__ /*src_function*/,
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"improperly placed sign indicator",
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(ix - tk_start),
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input_state_ref);
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}
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} else if (*ix == '.') {
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if (period_flag) {
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return result_type::make_error_consume_current_line
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(__FUNCTION__ /*src_function*/,
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"duplicate decimal point in numeric literal",
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(ix - tk_start),
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input_state_ref);
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}
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period_flag = true;
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} else if ((*ix == 'e') || (*ix == 'E')) {
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if (exponent_flag) {
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return result_type::make_error_consume_current_line
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(__FUNCTION__ /*src_function*/,
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"duplicate exponent marker in numeric literal",
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(ix - tk_start),
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input_state_ref);
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}
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exponent_flag = true;
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} else if (isdigit(*ix)) {
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if (exponent_flag) {
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/* need digit before exponent to recognize as number */
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exponent_digit_flag = true;
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} else {
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number_flag = true;
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}
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} else {
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return result_type::make_error_consume_current_line
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(__FUNCTION__ /*src_function*/,
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"unexpected character in numeric constant" /*error_description*/,
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(ix - tk_start),
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input_state_ref);
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}
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}
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if (number_flag) {
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if (period_flag || exponent_flag) {
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tk_type = tokentype::tk_f64;
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} else {
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tk_type = tokentype::tk_i64;
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}
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} else if (period_flag && !exponent_flag) {
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tk_type = tokentype::tk_dot;
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} else {
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/* not a valid token */
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}
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log && log(xtag("sign_flag", sign_flag));
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log && log(xtag("period_flag", period_flag),
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xtag("exponent_flag", exponent_flag),
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xtag("exponent_sign_flag", exponent_sign_flag),
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xtag("number_flag", number_flag));
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log && log(xtag("tk_type", tk_type));
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}
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break;
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}
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case '*':
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if (token_text.size() == 1) {
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/* standalone '*' */
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tk_type = tokentype::tk_star;
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++ix;
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} else {
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/* '*' isn't punctuation -- but may allow appearance in a longer token
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*
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* thinking that x*y is a symbol with an embedded '*' character;
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* in particular want to support kebab-case symbols like 'foo-config'
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*/
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}
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break;
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case '/':
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if (token_text.size() == 1) {
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/* standalone '/' */
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tk_type = tokentype::tk_slash;
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++ix;
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}
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break;
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case '=':
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log && log("singleassign or cmpeq token");
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if (*(ix + 1) == '=') {
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tk_type = tokentype::tk_cmpeq;
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++ix;
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++ix;
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} else {
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/* standalone '=' */
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tk_type = tokentype::tk_singleassign;
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++ix;
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}
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break;
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case '!':
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if (*(ix + 1) == '=') {
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tk_type = tokentype::tk_cmpne;
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++ix;
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++ix;
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} else {
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/* standlone '!' */
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// TODO
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}
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break;
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case '"':
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{
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log && log("recognize string-token");
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tk_type = tokentype::tk_string;
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tk_text.reserve(token_text.hi() - token_text.lo());
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++ix; /*skip initial " char*/
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/* true on final " */
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bool endofstring = false;
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for (; ix != token_text.hi(); ++ix) {
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log && log(xtag("*ix", *ix));
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switch(*ix) {
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case '"':
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endofstring = true;
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/* skip final " char, don't capture */
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++ix;
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break;
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case '\\':
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/* skip escape char, don't capture */
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++ix;
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if (ix == token_text.hi()) {
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return result_type::make_error_consume_current_line
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(__FUNCTION__ /*src_function*/,
|
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"expecting key following escape character \\",
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(ix - tk_start),
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input_state_ref);
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}
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switch(*ix) {
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case '\\':
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log && log(xtag("*ix", *ix), xtag("escaped", "t"));
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tk_text.push_back(*ix);
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break;
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case 'n':
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log && log(xtag("*ix", *ix), xtag("newline", "t"));
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tk_text.push_back('\n');
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break;
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case 't':
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log && log(xtag("*ix", *ix), xtag("tab", "t"));
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tk_text.push_back('\t');
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break;
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case 'r':
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log && log(xtag("*ix", *ix), xtag("cr", "t"));
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tk_text.push_back('\r');
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break;
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case '"':
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log && log(xtag("*ix", *ix), xtag("quote", "t"));
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tk_text.push_back('"');
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break;
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default:
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return result_type::make_error_consume_current_line
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(__FUNCTION__ /*src_function*/,
|
|
"expecting one of n|r|\"|\\ following escape \\",
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(ix - tk_start),
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input_state_ref);
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}
|
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break;
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default:
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tk_text.push_back(*ix);
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break;
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}
|
|
|
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if (endofstring)
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break;
|
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}
|
|
|
|
if (!endofstring) {
|
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return result_type::make_error_consume_current_line
|
|
(__FUNCTION__ /*src_function*/,
|
|
"missing terminating '\"' to complete literal string",
|
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(ix - tk_start),
|
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input_state_ref);
|
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}
|
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|
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log && log(tostr("tokenizer::assemble_token",
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xtag("tk_text", tk_text)));
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|
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break;
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}
|
|
case 'a': case 'A':
|
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case 'b': case 'B':
|
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case 'c': case 'C':
|
|
case 'd': case 'D':
|
|
case 'e': case 'E':
|
|
case 'f': case 'F':
|
|
case 'g': case 'G':
|
|
case 'h': case 'H':
|
|
case 'i': case 'I':
|
|
case 'j': case 'J':
|
|
case 'k': case 'K':
|
|
case 'l': case 'L':
|
|
case 'm': case 'M':
|
|
case 'n': case 'N':
|
|
case 'o': case 'O':
|
|
case 'p': case 'P':
|
|
case 'q': case 'Q':
|
|
case 'r': case 'R':
|
|
case 's': case 'S':
|
|
case 't': case 'T':
|
|
case 'u': case 'U':
|
|
case 'v': case 'V':
|
|
case 'w': case 'W':
|
|
case 'x': case 'X':
|
|
case 'y': case 'Y':
|
|
case 'z': case 'Z':
|
|
{
|
|
/* symbol/identifier must begin with a letter?
|
|
* we want to accept some other chars too.
|
|
* specifically want to allow identifiers:
|
|
* this-is-the-way
|
|
* this+is+also+the+way
|
|
* how/much/is/that/doggy
|
|
* put*an*asterisk*in*that
|
|
* something%special%
|
|
*
|
|
* like pure lisp, we don't allow:
|
|
* - identifier beginning with digit
|
|
* - period .
|
|
*
|
|
* unlike pure lisp, we don't allow anywhere in a symbol:
|
|
* - colon :
|
|
* - semicolon ;
|
|
* - comma ,
|
|
*
|
|
* also we don't allow symbols to begin with special chars
|
|
*/
|
|
|
|
tk_type = tokentype::tk_symbol;
|
|
break;
|
|
}
|
|
case '<':
|
|
{
|
|
log && log("leftangle or lessequal token");
|
|
|
|
if (*(ix + 1) == '=') {
|
|
tk_type = tokentype::tk_lessequal;
|
|
++ix;
|
|
++ix;
|
|
} else {
|
|
tk_type = tokentype::tk_leftangle;
|
|
++ix;
|
|
}
|
|
break;
|
|
}
|
|
case '>':
|
|
{
|
|
log && log("rightangle or greatequal token");
|
|
|
|
if (*(ix + 1) == '=') {
|
|
tk_type = tokentype::tk_greatequal;
|
|
++ix;
|
|
++ix;
|
|
} else {
|
|
tk_type = tokentype::tk_rightangle;
|
|
++ix;
|
|
}
|
|
break;
|
|
}
|
|
case '(':
|
|
tk_type = tokentype::tk_leftparen;
|
|
++ix;
|
|
break;
|
|
case ')':
|
|
tk_type = tokentype::tk_rightparen;
|
|
++ix;
|
|
break;
|
|
case '[':
|
|
tk_type = tokentype::tk_leftbracket;
|
|
++ix;
|
|
break;
|
|
case ']':
|
|
tk_type = tokentype::tk_rightbracket;
|
|
++ix;
|
|
break;
|
|
case '{':
|
|
tk_type = tokentype::tk_leftbrace;
|
|
++ix;
|
|
break;
|
|
case '}':
|
|
tk_type = tokentype::tk_rightbrace;
|
|
++ix;
|
|
break;
|
|
case ',':
|
|
tk_type = tokentype::tk_comma;
|
|
++ix;
|
|
break;
|
|
case ';':
|
|
tk_type = tokentype::tk_semicolon;
|
|
++ix;
|
|
break;
|
|
case ':':
|
|
{
|
|
log && log("colon or assignment token");
|
|
|
|
if (*(ix + 1) == '=') {
|
|
tk_type = tokentype::tk_assign;
|
|
++ix;
|
|
++ix;
|
|
} else {
|
|
tk_type = tokentype::tk_colon;
|
|
++ix;
|
|
}
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (tk_type == tokentype::tk_invalid) {
|
|
return result_type::make_error_consume_current_line
|
|
(__FUNCTION__ /*src_function*/,
|
|
"illegal input character",
|
|
(ix - tk_start),
|
|
input_state_ref);
|
|
}
|
|
|
|
if ((tk_type == tokentype::tk_i64)
|
|
|| (tk_type == tokentype::tk_f64)
|
|
|| (tk_type == tokentype::tk_symbol))
|
|
{
|
|
/* note: capturing token text here;
|
|
* for numeric literals will re-parse in token::i64_value() / token::f64_value()
|
|
*/
|
|
tk_text = std::string(tk_start, tk_end);
|
|
} else if (tk_type == tokentype::tk_string) {
|
|
; /* nothing to do here -- desired tk_text already constructed */
|
|
}
|
|
|
|
if (tk_type == tokentype::tk_symbol) {
|
|
/* check for keywords */
|
|
|
|
bool keep_text = false;
|
|
|
|
if ((tk_text == "true") || (tk_text == "false")) {
|
|
tk_type = tokentype::tk_bool;
|
|
keep_text = true;
|
|
} else if (tk_text == "type") {
|
|
tk_type = tokentype::tk_type;
|
|
} else if (tk_text == "def") {
|
|
tk_type = tokentype::tk_def;
|
|
} else if (tk_text == "lambda") {
|
|
tk_type = tokentype::tk_lambda;
|
|
} else if (tk_text == "if") {
|
|
tk_type = tokentype::tk_if;
|
|
} else if (tk_text == "then") {
|
|
tk_type = tokentype::tk_then;
|
|
} else if (tk_text == "else") {
|
|
tk_type = tokentype::tk_else;
|
|
} else if (tk_text == "let") {
|
|
tk_type = tokentype::tk_let;
|
|
} else if (tk_text == "in") {
|
|
tk_type = tokentype::tk_in;
|
|
} else if (tk_text == "end") {
|
|
tk_type = tokentype::tk_end;
|
|
} else {
|
|
/* keep as symbol */
|
|
keep_text = true;
|
|
}
|
|
|
|
if (!keep_text)
|
|
tk_text.clear();
|
|
}
|
|
|
|
/* input.prefix(0):
|
|
* require caller preserves current input line until it's entirely exhausted
|
|
*/
|
|
return result_type(token_type(tk_type, std::move(tk_text)),
|
|
input_state_ref.current_line().prefix(0));
|
|
} /*assemble_token*/
|
|
|
|
/* TODO: input_state_ as argument ? */
|
|
template <typename CharT>
|
|
auto
|
|
tokenizer<CharT>::assemble_final_token(const span_type & token_text,
|
|
const input_state_type & input_state) -> result_type
|
|
{
|
|
return assemble_token(0 /*initial_whitespace*/,
|
|
token_text,
|
|
input_state);
|
|
}
|
|
|
|
template <typename CharT>
|
|
auto
|
|
tokenizer<CharT>::scan(const span_type & input,
|
|
bool eof_flag) -> result_type
|
|
{
|
|
scope log(XO_DEBUG(input_state_.debug_flag()));
|
|
|
|
log && log(xtag("input", input));
|
|
|
|
/* - Always at beginning of token when scan() invoked
|
|
* - scan will not report any portion of line as consumed until it has
|
|
* emitted all tokens in that line.
|
|
* rationale: caller is allowed to discard storage that
|
|
* scan() reports as consumed. But will be holding that line
|
|
* until all tokens have been read.
|
|
* - this means caller will typically call scan()
|
|
* with the same input span multiple times
|
|
*/
|
|
|
|
/* automagically no-ops when the same input presented twice */
|
|
this->input_state_.capture_current_line(input, eof_flag);
|
|
|
|
const CharT * ix = this->input_state_.skip_leading_whitespace();
|
|
|
|
if(ix == input.hi()) {
|
|
log && log("end input -> consume current line");
|
|
|
|
/* entirety of current line has been tokenized
|
|
* -> caller may consume it
|
|
*/
|
|
return result_type::make_whitespace(this->input_state_.consume_current_line());
|
|
}
|
|
|
|
/* ix: if ix < input.hi: first non-whitespace character after input_state_.current_pos_ */
|
|
|
|
// TODO:
|
|
// 1. hoist complete_flag up here
|
|
// 2. use in each branch
|
|
// 3. common check for prefix-capturing after if-cascade below done
|
|
|
|
/* here: *ix is not whitespace */
|
|
|
|
auto whitespace_z = input_state_.whitespace();
|
|
|
|
log && log(xtag("whitespace_z", whitespace_z));
|
|
|
|
/* tk_start points to known beginning of token
|
|
* (after any whitespace)
|
|
*
|
|
* goal is to leave ix pointing to 1 char past the end of the token
|
|
*/
|
|
const CharT * tk_start = ix;
|
|
|
|
if (is_1char_punctuation(*ix)) {
|
|
/* 1-character token */
|
|
++ix;
|
|
} else if (is_2char_punctuation(*ix)) {
|
|
CharT ch1 = *ix;
|
|
|
|
(void)ch1;
|
|
|
|
++ix;
|
|
|
|
#ifdef OBSOLETE // no longer a thing. either input ends in whitespace, or ends translation unit
|
|
if (ix == input.hi()) {
|
|
/* need more input to know if/when token complete */
|
|
this->prefix_ += std::string(tk_start, input.hi());
|
|
|
|
log && log(xtag("captured-prefix1", this->prefix_));
|
|
} else
|
|
#endif
|
|
{
|
|
CharT ch2 = *ix;
|
|
|
|
if (((ch2 >= '0') && (ch2 <= '9'))
|
|
|| ((ch2 >= 'A') && (ch2 <= 'Z'))
|
|
|| ((ch2 >= 'a') && (ch2 <= 'z')))
|
|
{
|
|
/* treat as 1 char punctuation */
|
|
;
|
|
} else {
|
|
/* include next char */
|
|
++ix;
|
|
}
|
|
}
|
|
} else if (*ix == '"') {
|
|
bool complete_flag = false;
|
|
|
|
/* 1. embedded space/tab allowed in string literal.
|
|
* 2. embedded newline/cr not allowed.
|
|
*/
|
|
CharT prev_ch = '"';
|
|
|
|
++ix;
|
|
|
|
for (; ix != input.hi(); ++ix) {
|
|
/* looking for unescaped " char to end literal */
|
|
if (*ix == '"') {
|
|
if (prev_ch != '\\') {
|
|
++ix; /* include terminating " for assemble_token */
|
|
complete_flag = true;
|
|
break;
|
|
}
|
|
} else if ((*ix == '\n') || (*ix == '\r')) {
|
|
log && log ("string literal with naked newline or CR");
|
|
|
|
return result_type::make_error_consume_current_line
|
|
(__FUNCTION__ /*src_function*/,
|
|
"must use \\n or \\r to encode newline/cr in string literal",
|
|
(ix - tk_start),
|
|
this->input_state_);
|
|
}
|
|
|
|
prev_ch = *ix;
|
|
}
|
|
|
|
if (!complete_flag) {
|
|
log && log("unterminated string literal");
|
|
|
|
return result_type::make_error_consume_current_line
|
|
(__FUNCTION__ /*src_function*/,
|
|
"unterminated string literal",
|
|
(ix - tk_start),
|
|
this->input_state_);
|
|
}
|
|
} else {
|
|
/* ix is start of some token */
|
|
|
|
if (*ix == '-') {
|
|
/* this section load-bearing for input '->' scanning from beginning of token */
|
|
++ix;
|
|
|
|
if (ix == input.hi()) {
|
|
/* need more input to know if/when token complete -- see captured-prefix5 below */
|
|
} else {
|
|
CharT ch2 = *ix;
|
|
|
|
if (ch2 == '>') {
|
|
/* include next char and complete token */
|
|
++ix;
|
|
|
|
log && log("complete '->' token");
|
|
|
|
this->input_state_.advance_until(ix);
|
|
|
|
return assemble_token(whitespace_z,
|
|
span_type(tk_start, ix) /*token*/,
|
|
input_state_);
|
|
}
|
|
|
|
/* here: -123, -.5e-21 for example */
|
|
}
|
|
} else if (*ix == '>') {
|
|
/* this section load-bearing for input '>=' scanning from beginning of token.
|
|
* Need this because '>' necessarily excluded from is_1char_punctuation()
|
|
*/
|
|
++ix;
|
|
|
|
if (ix == input.hi()) {
|
|
/* need more input to know if/when token complete -- see captured-prefix5 below */
|
|
} else {
|
|
CharT ch2 = *ix;
|
|
|
|
if (ch2 != '=') {
|
|
log && log("complete '>=' token");
|
|
|
|
this->input_state_.advance_until(ix);
|
|
|
|
/* ignore next char and complete token */
|
|
return assemble_token(whitespace_z,
|
|
span_type(tk_start, ix) /*token*/,
|
|
this->input_state_);
|
|
}
|
|
|
|
/* here: >= for example */
|
|
}
|
|
}
|
|
|
|
/* scan until:
|
|
* - whitespace
|
|
* - punctuation
|
|
*/
|
|
for (; ix != input.hi(); ++ix) {
|
|
if (input_state_type::is_whitespace(*ix)
|
|
|| is_1char_punctuation(*ix)
|
|
|| is_2char_punctuation(*ix))
|
|
{
|
|
break;
|
|
}
|
|
|
|
/* this section load-bearing for input '>' after beginning of a token, e.g. p> */
|
|
if ((ix > tk_start) && (*ix == '>'))
|
|
break;
|
|
|
|
/* this section load-bearing for input '->' at the end of another token, e.g. p->q */
|
|
if (*ix == '-') {
|
|
if (ix + 1 == input.hi()) {
|
|
/* need more input to know if/when token complete
|
|
*
|
|
* apple-banana parses as: {tk_symbol: apple-banana}
|
|
* apple-> parses as: {tk_symbol: apple} {tk_yields}
|
|
* apple- illegal (may not end symbol with '-')
|
|
*/
|
|
break;
|
|
}
|
|
|
|
if (*(ix + 1) == '>') {
|
|
/* treat '->' as punctuation; complete preceding token */
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef OBSOLETE
|
|
if (ix == input.hi()) {
|
|
/* need more input to know if/when token complete */
|
|
this->prefix_ += std::string(tk_start, input.hi());
|
|
|
|
log && log(xtag("captured-prefix5", this->prefix_));
|
|
}
|
|
#endif
|
|
}
|
|
|
|
log && log("assemble token z", xtag("token_z", ix - tk_start));
|
|
|
|
assert(tk_start < ix);
|
|
|
|
this->input_state_.advance_until(ix);
|
|
|
|
return assemble_token(whitespace_z,
|
|
span_type(tk_start, ix) /*token*/,
|
|
this->input_state_);
|
|
} /*scan*/
|
|
|
|
#ifdef OBSOLETE
|
|
template <typename CharT>
|
|
auto
|
|
tokenizer<CharT>::scan2(const span_type & input, bool eof) -> result_type {
|
|
scope log(XO_DEBUG(input_state_.debug_flag()));
|
|
|
|
auto sr = this->scan(input);
|
|
|
|
if (sr.is_token() || sr.is_error() || !eof)
|
|
return sr;
|
|
|
|
/* control here only if input contains no unambiguous tokens.
|
|
* This implies it contains _at most one_ final token.
|
|
*/
|
|
|
|
span_type input2 = input.after_prefix(sr.consumed());
|
|
|
|
/* need to include src.consumed() in retval */
|
|
|
|
auto sr2 = this->notify_eof(input2);
|
|
|
|
return result_type(sr2.get_token(),
|
|
span_type::concat(sr.consumed(), sr2.consumed()),
|
|
sr2.error());
|
|
}
|
|
#endif
|
|
|
|
#ifdef OBSOLETE
|
|
template <typename CharT>
|
|
auto
|
|
tokenizer<CharT>::consume(const span_type & consumed,
|
|
const span_type & input) -> span_type
|
|
{
|
|
this->input_state_.consume(consumed.size());
|
|
|
|
return input.after_prefix(consumed);
|
|
}
|
|
#endif
|
|
|
|
template <typename CharT>
|
|
void
|
|
tokenizer<CharT>::discard_current_line()
|
|
{
|
|
this->input_state_.discard_current_line();
|
|
}
|
|
|
|
#ifdef OBSOLETE
|
|
template <typename CharT>
|
|
auto
|
|
tokenizer<CharT>::notify_eof(const span_type & input) -> result_type {
|
|
scope log(XO_DEBUG(input_state_.debug_flag()));
|
|
|
|
log && log(xtag("prefix_", prefix_), xtag("prefix_.size", prefix_.size()), xtag("input", input));
|
|
|
|
/* almost meretricious to include input here,
|
|
* when called from scan2() it can only be whitespace
|
|
*/
|
|
return result_type::make_whitespace(input);
|
|
} /*notify_eof*/
|
|
#endif
|
|
} /*namespace scm*/
|
|
} /*namespace xo*/
|
|
|
|
/* end tokenizer.hpp */
|