xo-reader: refactor: simplify define_xs behavior

This commit is contained in:
Roland Conybeare 2024-08-18 23:29:36 -04:00
commit 818127a446
4 changed files with 110 additions and 181 deletions

View file

@ -1,48 +1,30 @@
/* @file define_xs.cpp */
#include "define_xs.hpp"
#include "expect_symbol_xs.hpp"
#include "expect_expr_xs.hpp"
#include "expect_type_xs.hpp"
namespace xo {
namespace scm {
std::unique_ptr<define_xs>
define_xs::def_0() {
define_xs::make() {
return std::make_unique<define_xs>(define_xs(DefineExprAccess::make_empty()));
}
void
define_xs::start(exprstatestack * p_stack)
{
p_stack->push_exprstate(define_xs::make());
p_stack->top_exprstate().on_def_token(token_type::def(), p_stack);
}
define_xs::define_xs(rp<DefineExprAccess> def_expr)
: exprstate(exprstatetype::defexpr),
defxs_type_{defexprstatetype::def_0},
def_expr_{std::move(def_expr)}
{}
bool
define_xs::admits_colon() const {
switch (defxs_type_) {
case defexprstatetype::def_0:
return false;
case defexprstatetype::def_1:
return true;
case defexprstatetype::def_2:
case defexprstatetype::def_3:
case defexprstatetype::def_4:
case defexprstatetype::def_5:
return false;
case defexprstatetype::invalid:
case defexprstatetype::n_defexprstatetype:
/* unreachable */
assert(false);
return false;
}
return false;
}
bool
define_xs::admits_semicolon() const {
switch (defxs_type_) {
@ -52,8 +34,9 @@ namespace xo {
case defexprstatetype::def_2:
case defexprstatetype::def_3:
case defexprstatetype::def_4:
return false;
case defexprstatetype::def_5:
return false;
case defexprstatetype::def_6:
return true;
case defexprstatetype::invalid:
@ -66,73 +49,6 @@ namespace xo {
return false;
}
#ifdef OBSOLETE
bool
define_xs::admits_singleassign() const {
switch (defxs_type_) {
case defexprstatetype::def_0:
return false;
case defexprstatetype::def_1:
return true;
case defexprstatetype::def_2:
return false;
case defexprstatetype::def_3:
return true;
case defexprstatetype::def_4:
case defexprstatetype::def_5:
return false;
case defexprstatetype::invalid:
case defexprstatetype::n_defexprstatetype:
/* unreachable */
assert(false);
return false;
}
return false;
}
#endif
#ifdef OBSOLETE
bool
define_xs::admits_leftparen() const {
switch (defxs_type_) {
case defexprstatetype::def_0:
case defexprstatetype::def_1:
case defexprstatetype::def_2:
case defexprstatetype::def_3:
case defexprstatetype::def_4:
case defexprstatetype::def_5:
/* input like
* def foo : f64 = (
* ^ ^ ^ ^ ^
* | | | | def_4
* | | | def_3
* | | def_2
* | def_1
* def_0
*
* not allowed or relies on pushing another state
*/
return false;
case defexprstatetype::invalid:
case defexprstatetype::n_defexprstatetype:
/* unreachable */
assert(false);
return false;
}
return false;
}
#endif
bool
define_xs::admits_rightparen() const {
switch (defxs_type_) {
@ -143,6 +59,7 @@ namespace xo {
case defexprstatetype::def_3:
case defexprstatetype::def_4:
case defexprstatetype::def_5:
case defexprstatetype::def_6:
return false;
case defexprstatetype::invalid:
@ -166,10 +83,11 @@ namespace xo {
case defexprstatetype::def_1:
case defexprstatetype::def_2:
case defexprstatetype::def_3:
case defexprstatetype::def_4:
/* NOT IMPLEMENTED */
assert(false);
return;
case defexprstatetype::def_4: {
case defexprstatetype::def_5: {
/* have all the ingredients to create an expression
* representing a definition
*
@ -186,11 +104,11 @@ namespace xo {
rp<Expression> def_expr = this->def_expr_;
this->defxs_type_ = defexprstatetype::def_5;
this->defxs_type_ = defexprstatetype::def_6;
return;
}
case defexprstatetype::def_5:
case defexprstatetype::def_6:
assert(false);
return;
@ -209,16 +127,20 @@ namespace xo {
{
switch (this->defxs_type_) {
case defexprstatetype::def_0:
this->defxs_type_ = defexprstatetype::def_1;
assert(false);
return;
case defexprstatetype::def_1:
this->defxs_type_ = defexprstatetype::def_2;
this->def_expr_->assign_lhs_name(symbol_name);
//this->def_lhs_symbol_ = symbol_name;
return;
case defexprstatetype::def_1:
case defexprstatetype::def_2:
case defexprstatetype::def_3:
case defexprstatetype::def_4:
case defexprstatetype::def_5:
case defexprstatetype::def_6:
/* NOT IMPLEMENTED */
assert(false);
return;
@ -240,12 +162,13 @@ namespace xo {
case defexprstatetype::def_0:
case defexprstatetype::def_1:
case defexprstatetype::def_2:
/* NOT IMPLEMENTED (ill-formed program) */
assert(false);
return;
case defexprstatetype::def_2:
this->defxs_type_ = defexprstatetype::def_3;
case defexprstatetype::def_3:
this->defxs_type_ = defexprstatetype::def_4;
this->cvt_expr_ = ConvertExprAccess::make(td /*dest_type*/,
nullptr /*source_expr*/);
this->def_expr_->assign_rhs(this->cvt_expr_);
@ -253,9 +176,9 @@ namespace xo {
return;
case defexprstatetype::def_3:
case defexprstatetype::def_4:
case defexprstatetype::def_5:
case defexprstatetype::def_6:
/* NOT IMPLEMENTED */
assert(false);
return;
@ -269,28 +192,38 @@ namespace xo {
}
void
define_xs::on_colon_token(const token_type & /*tk*/,
define_xs::on_def_token(const token_type & tk,
exprstatestack * p_stack)
{
constexpr bool c_debug_flag = true;
scope log(XO_DEBUG(c_debug_flag));
//constexpr const char * self_name = "define_xs::on_def_token";
if (this->defxs_type_ == defexprstatetype::def_0) {
this->defxs_type_ = defexprstatetype::def_1;
p_stack->push_exprstate(expect_symbol_xs::expect_symbol_expression());
} else {
exprstate::on_def_token(tk, p_stack);
}
}
void
define_xs::on_colon_token(const token_type & tk,
exprstatestack * p_stack)
{
constexpr bool c_debug_flag = true;
scope log(XO_DEBUG(c_debug_flag));
constexpr const char * self_name = "exprstate::on_colon";
//constexpr const char * self_name = "define_xs::on_colon_token";
/* lots of illegal states */
if (!this->admits_colon())
{
throw std::runtime_error(tostr(self_name,
": unexpected colon for parsing state",
xtag("state", *this)));
}
if (this->defxs_type_ == defexprstatetype::def_1) {
this->defxs_type_ = defexprstatetype::def_2;
if (this->defxs_type_ == defexprstatetype::def_2) {
this->defxs_type_ = defexprstatetype::def_3;
p_stack->push_exprstate(expect_type_xs::make());
} else {
assert(false);
exprstate::on_colon_token(tk, p_stack);
}
}
@ -311,7 +244,7 @@ namespace xo {
xtag("state", *this)));
}
if (this->defxs_type_ == defexprstatetype::def_5) {
if (this->defxs_type_ == defexprstatetype::def_6) {
rp<Expression> expr = this->def_expr_;
std::unique_ptr<exprstate> self = p_stack->pop_exprstate();
@ -336,21 +269,22 @@ namespace xo {
/*
* def foo = 1 ;
* def foo : f64 = 1 ;
* ^ ^ ^ ^ ^ ^ ^
* | | | | | | (done)
* | | | | | def_4:expect_rhs_expression
* | | | | def_3
* | | | def_2:expect_type
* | | def_1
* | def_0:expect_symbol
* ^ ^ ^ ^ ^ ^ ^ ^
* | | | | | | | (done)
* | | | | | | def_6
* | | | | | def_5:expect_rhs_expression
* | | | | def_4
* | | | def_3:expect_type
* | | def_2
* | def_1:expect_symbol
* expect_toplevel_expression_sequence
*
* note that we skip from def_1 -> def_4 if '=' instead of ':'
* note that we skip from def_2 -> def_5 if '=' instead of ':'
*/
if ((this->defxs_type_ == defexprstatetype::def_1)
|| (this->defxs_type_ == defexprstatetype::def_3))
if ((this->defxs_type_ == defexprstatetype::def_2)
|| (this->defxs_type_ == defexprstatetype::def_4))
{
this->defxs_type_ = defexprstatetype::def_4;
this->defxs_type_ = defexprstatetype::def_5;
p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
} else {
@ -358,23 +292,6 @@ namespace xo {
}
}
#ifdef OBSOLETE
void
define_xs::on_leftparen_token(const token_type & tk,
exprstatestack * /*p_stack*/,
rp<Expression> * /*p_emit_expr*/)
{
constexpr bool c_debug_flag = true;
scope log(XO_DEBUG(c_debug_flag));
constexpr const char * self_name = "exprstate::on_leftparen";
this->illegal_input_error(self_name, tk);
assert(false); /* inserting this during refactor...? */
}
#endif
void
define_xs::on_rightparen_token(const token_type & tk,
exprstatestack * /*p_stack*/,

View file

@ -26,12 +26,7 @@ namespace xo {
//constexpr const char * c_self_name = "exprseq_xs::on_def_token";
p_stack->push_exprstate(define_xs::def_0());
/* todo: replace:
* expect_symbol_or_function_signature()
*/
p_stack->push_exprstate(expect_symbol_xs::expect_symbol_expression());
define_xs::start(p_stack);
/* keyword 'def' introduces a definition:
* def pi : f64 = 3.14159265