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xo-parser: simplify: + exprstate::on_expr split from on_exprir()

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This commit is contained in:
Roland Conybeare 2024-08-01 13:23:16 +10:00
commit 514a2cb687
2 changed files with 71 additions and 10 deletions
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4
include/xo/parser/parser.hpp
View file

@ -223,6 +223,10 @@ namespace xo {
* forward instructions to parent parser
**/
void on_input(const token_type & tk, exprstatestack * p_stack, rp<Expression> * p_emit_expr);
/** update exprstate in response to a successfully-parsed subexpression **/
void on_expr(ref::brw<Expression> expr,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr);
/** update exprstate in response to IR (intermediate representation)
* from nested parsing task
**/

77
src/parser/parser.cpp
View file

@ -313,8 +313,7 @@ namespace xo {
/* have to do pop first */
p_stack->pop_exprstate();
p_stack->top_exprstate().on_exprir
(exprir(exprirtype::symbol, tk.text()), p_stack, p_emit_expr);
p_stack->top_exprstate().on_exprir(exprir(exprirtype::symbol, tk.text()), p_stack, p_emit_expr);
//return expraction::pop(exprir(exprirtype::symbol, tk.text()));
return;
@ -424,11 +423,9 @@ namespace xo {
if (this->exs_type_ == exprstatetype::expect_rhs_expression) {
p_stack->pop_exprstate();
p_stack->top_exprstate()
.on_exprir(exprir(exprirtype::expression,
Constant<double>::make(tk.f64_value())),
p_stack,
p_emit_expr);
p_stack->top_exprstate().on_expr(Constant<double>::make(tk.f64_value()),
p_stack,
p_emit_expr);
} else {
assert(false);
}
@ -516,6 +513,67 @@ namespace xo {
assert(false);
}
void
exprstate::on_expr(ref::brw<Expression> expr,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr)
{
switch(this->exs_type_) {
case exprstatetype::expect_toplevel_expression_sequence:
/* toplevel expression sequence accepts an
* arbitrary number of expressions.
*
* parser::include_token() returns
*/
*p_emit_expr = expr.get();
return;
case exprstatetype::def_0:
case exprstatetype::def_1:
case exprstatetype::def_2:
case exprstatetype::def_3:
/* NOT IMPLEMENTED */
assert(false);
return;
case exprstatetype::def_4: {
/* have all the ingredients to create an expression
* representing a definition
*
* 1. if ir_type is a symbol, interpret as variable name.
* Need to be able to locate variable by type
* 2. if ir_type is an expression, adopt as rhs
*/
rp<Expression> rhs_value = expr.get();
if (def_lhs_td_)
rhs_value = ConvertExpr::make(def_lhs_td_, rhs_value);
rp<Expression> def = DefineExpr::make(this->def_lhs_symbol_,
rhs_value);
p_stack->pop_exprstate();
p_stack->top_exprstate().on_expr(def,
p_stack,
p_emit_expr);
return;
}
case exprstatetype::expect_rhs_expression:
case exprstatetype::expect_type:
case exprstatetype::expect_symbol:
/* unreachable
* (this exprstate issues pop instruction from exprstate::on_input()
*/
assert(false);
return;
case exprstatetype::invalid:
case exprstatetype::n_exprstatetype:
/* unreachable */
assert(false);
return;
}
}
void
exprstate::on_exprir(const exprir & ir,
exprstatestack * p_stack,
@ -580,9 +638,8 @@ namespace xo {
rhs_value);
p_stack->pop_exprstate();
return p_stack->top_exprstate()
.on_exprir(exprir(exprirtype::expression, def),
p_stack, p_emit_expr);
return p_stack->top_exprstate().on_expr(def,
p_stack, p_emit_expr);
} else {
assert(false);
return;