226 lines
9.2 KiB
C++
226 lines
9.2 KiB
C++
/* file Token.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 "tokentype.hpp"
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#include "xo/indentlog/print/tag.hpp"
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#include <stdexcept>
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#include <ostream>
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#include <string>
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#include <cstdint>
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namespace xo {
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namespace scm {
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namespace detail {
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/* compute a * b^p, p >= 0 */
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constexpr double
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pow_aux(double a, double b, int p) {
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while (p > 0) {
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if (p % 2 == 1) {
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/* a * b^p = a * b^(2q + 1) = a.b * 10^(2q) */
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a *= b;
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p -= 1;
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} else {
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/* a * b^p = a * b^(2q) = a * (b^2)^q */
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b = b * b;
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p /= 2;
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}
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}
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/* a * b^0 = a */
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return a;
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}
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constexpr double
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pow10(int p) {
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if (p >= 0)
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return pow_aux(1.0, 10.0, p);
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else
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return 1.0 / pow_aux(1.0, 10.0, -p);
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}
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}
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/** @class token
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* @brief Represent a Schematika lexical token
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**/
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class Token {
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public:
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/** @defgroup token-ctors token constructors **/
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///@{
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/** default ctor creates token with type @c tk_invalid **/
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Token() = default;
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/** create token with type @c tk_type and input text @c text **/
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Token(tokentype tk_type, const std::string & text = "")
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: tk_type_{tk_type}, text_{text} {}
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/** create invalid token (same as null ctor, but explicit) **/
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static Token invalid() { return Token(); }
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/** Create token representing a boolean literal from text @p txt
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* @p txt must be @c true or @c false
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**/
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static Token bool_token(const std::string & txt) {
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return Token(tokentype::tk_bool, txt);
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}
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/** Create token representing 64-bit signed integer literal parsed from decimal @p txt.
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* The string @p txt must be a decimal integer literal, since @ref i64_value re-parses @p txt.
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**/
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static Token i64_token(const std::string & txt) {
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return Token(tokentype::tk_i64, txt);
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}
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/** create token representing 64-bit floating-point literal parsed from decimal @p txt
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* The string @p txt must be a decimal floating-point literal, since @ref f64_value re-parses @p txt.
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**/
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static Token f64_token(const std::string & txt) {
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return Token(tokentype::tk_f64, txt);
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}
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/** create token representing literal string parsed from @p txt **/
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static Token string_token(const std::string & txt) {
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return Token(tokentype::tk_string, txt);
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}
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/** create token representing a symbol parsed from @p txt.
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* Note that not all strings are valid symbol names.
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**/
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static Token symbol_token(const std::string & txt) {
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return Token(tokentype::tk_symbol, txt);
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}
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/** token representing left angle bracket @c "<" **/
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static Token leftangle() { return Token(tokentype::tk_leftangle); }
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/** token representing right angle bracket @c ">" **/
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static Token rightangle() { return Token(tokentype::tk_rightangle); }
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/** token representing left parenthesis @c "(" **/
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static Token leftparen() { return Token(tokentype::tk_leftparen); }
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/** Token representing right parenthesis @c ")" **/
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static Token rightparen() { return Token(tokentype::tk_rightparen); }
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/** token representing left bracket @c "[" **/
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static Token leftbracket() { return Token(tokentype::tk_leftbracket); }
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/** token representing right bracket @c "]" **/
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static Token rightbracket() { return Token(tokentype::tk_rightbracket); }
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/** token representing left brace @c "{" **/
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static Token leftbrace() { return Token(tokentype::tk_leftbrace); }
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/** token representing right brace @c "}' **/
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static Token rightbrace() { return Token(tokentype::tk_rightbrace); }
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/** token representing period @c "." **/
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static Token dot() { return Token(tokentype::tk_dot); }
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/** token representing comma @c "," **/
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static Token comma() { return Token(tokentype::tk_comma); }
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/** token representing colon @c ":" **/
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static Token colon() { return Token(tokentype::tk_colon); }
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/** token representing double-colo @c "::" **/
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static Token doublecolon() { return Token(tokentype::tk_doublecolon); }
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/** token representing semicolon @c ";" **/
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static Token semicolon() { return Token(tokentype::tk_semicolon); }
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/** token representing single-assignment @c "=" **/
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static Token singleassign() { return Token(tokentype::tk_singleassign); }
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/** token representing unrestricted assignment @c ":=" **/
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static Token assign_token() { return Token(tokentype::tk_assign); }
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/** token representing indirection @c "->" **/
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static Token yields() { return Token(tokentype::tk_yields); }
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/** token for @c "+" **/
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static Token plus_token() { return Token(tokentype::tk_plus); }
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/** token for @c "-" **/
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static Token minus_token() { return Token(tokentype::tk_minus); }
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/** token for @c "*" **/
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static Token star_token() { return Token(tokentype::tk_star); }
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/** token for @c "/" **/
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static Token slash_token() { return Token(tokentype::tk_slash); }
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/** token representing keyword @c type **/
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static Token type() { return Token(tokentype::tk_type); }
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/** token representing keyword @c def **/
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static Token def_token() { return Token(tokentype::tk_def); }
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/** token representing keyword @c lambda **/
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static Token lambda() { return Token(tokentype::tk_lambda); }
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/** token representing keyword @c if **/
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static Token if_token() { return Token(tokentype::tk_if); }
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/** token representing keyword @c else **/
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static Token else_token() { return Token(tokentype::tk_else); }
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/** token representing keyword @c let **/
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static Token let() { return Token(tokentype::tk_let); }
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/** token representing keyword @c in **/
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static Token in() { return Token(tokentype::tk_in); }
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/** token representing keyword @c end **/
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static Token end() { return Token(tokentype::tk_end); }
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///@}
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/** @defgroup token-access-methods **/
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///@{
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tokentype tk_type() const { return tk_type_; }
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const std::string & text() const { return text_; }
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///@}
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/** @defgroup token-general-methods **/
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///@{
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/** true if token understood to represent valid input
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* i.e. any token type except @c tk_invalid
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**/
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bool is_valid() const { return tk_type_ != tokentype::tk_invalid; }
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/** true for sentinel token with type tk_invalid **/
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bool is_invalid() const { return tk_type_ == tokentype::tk_invalid; }
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/** true for tokens with variable text. false for those with fixed textual representation **/
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bool has_variable_text() const { return (tk_type_ == tokentype::tk_i64
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|| tk_type_ == tokentype::tk_f64
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|| tk_type_ == tokentype::tk_string
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|| tk_type_ == tokentype::tk_symbol); }
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/** expect input matching @c true or @c false **/
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bool bool_value() const;
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/** expect input matching @c [+|-][0-9][0-9]* **/
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std::int64_t i64_value() const;
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/** expect input matching @c [+|-][0-9]*[.][0-9]*[e|E][+|-][0-9]* **/
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double f64_value() const;
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/** print human-readable token representation on stream @p os **/
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void print(std::ostream & os) const;
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///@}
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private:
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/** @defgroup token-instance-vars **/
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///@{
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/** category for this token **/
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tokentype tk_type_ = tokentype::tk_invalid;
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/** characters comprising this token.
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* only provided for certain token types:
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*
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* tk_i64
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* tk_f64
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* tk_string
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* tk_symbol
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**/
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std::string text_;
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///@}
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};
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inline std::ostream &
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operator<< (std::ostream & os,
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const Token & tk)
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{
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tk.print(os);
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return os;
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}
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} /*namespace scm*/
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#ifndef ppdetail_atomic
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namespace print {
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PPDETAIL_ATOMIC(xo::scm::token<char>);
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}
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#endif
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} /*namespace xo*/
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/* end Token.hpp */
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