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xo-reader: streamline: simplify expect_expr_xs

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This commit is contained in:
Roland Conybeare 2024-08-10 15:56:48 -05:00
commit d1d72f9fc9
4 changed files with 69 additions and 112 deletions
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112
src/reader/exprstate.cpp
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@ -50,14 +50,11 @@ namespace xo {
case exprstatetype::defexpr:
case exprstatetype::parenexpr:
case exprstatetype::expect_rhs_expression:
/* unreachable */
assert(false);
return false;
case exprstatetype::expect_rhs_expression:
/* treat symbol as variable name */
return true;
case exprstatetype::expect_symbol:
return true;
@ -179,40 +176,6 @@ namespace xo {
return false;
}
#ifdef OBSOLETE
bool
exprstate::admits_rightparen() const {
switch (exs_type_) {
case exprstatetype::expect_toplevel_expression_sequence:
return false;
case exprstatetype::defexpr:
case exprstatetype::parenexpr:
/* unreachable - redirects to define_xs */
assert(false);
return false;
case exprstatetype::expect_rhs_expression:
return false;
case exprstatetype::expect_type:
return false;
case exprstatetype::expect_symbol:
return false;
case exprstatetype::expr_progress:
case exprstatetype::invalid:
case exprstatetype::n_exprstatetype:
/* unreachable */
assert(false);
return false;
}
return false;
}
#endif
void
exprstate::on_def_token(const token_type & tk,
exprstatestack * /*p_stack*/)
@ -240,39 +203,11 @@ namespace xo {
case exprstatetype::expect_toplevel_expression_sequence:
case exprstatetype::defexpr:
case exprstatetype::parenexpr:
/* unreachable - redirects to define_xs */
case exprstatetype::expect_rhs_expression:
/* unreachable - redirected to define_xs etc */
assert(false);
return;
case exprstatetype::expect_rhs_expression:
{
/* various possibilities when looking for rhs expression:
*
* x := y // (1)
* x := f(a) // (2)
* x := f(a,b) // (3)
*
* need lookahead token following symbol to distinguish
* between (1) (symbol completes rhs expression)
* and {(2), (3)} (symbol is function call)
*/
/* have to do pop first, before sending symbol to
* the o.g. symbol-requester
*/
#ifdef NOT_YET
p_stack->push_exprstate(exprstate(exprstatetype::expr_progress,
Variable::make(name, type)));
#endif
#ifdef LATER
p_stack->pop_exprstate();
p_stack->top_exprstate().on_symbol(tk.text(),
p_stack, p_emit_expr);
#endif
return;
}
case exprstatetype::expect_symbol:
{
/* have to do pop first, before sending symbol to
@ -528,8 +463,8 @@ namespace xo {
void
exprstate::on_expr(ref::brw<Expression> expr,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr)
exprstatestack * /*p_stack*/,
rp<Expression> * /*p_emit_expr*/)
{
constexpr bool c_debug_flag = true;
scope log(XO_DEBUG(c_debug_flag));
@ -537,42 +472,7 @@ namespace xo {
log && log(xtag("exstype", this->exs_type_),
xtag("expr", expr));
switch (this->exs_type_) {
case exprstatetype::expect_toplevel_expression_sequence:
case exprstatetype::defexpr:
case exprstatetype::parenexpr:
/* unreachable. redirects to define_xs::on_expr() etc */
assert(false);
return;
case exprstatetype::expect_rhs_expression: {
std::unique_ptr<exprstate> self = p_stack->pop_exprstate();
p_stack->top_exprstate().on_expr(expr,
p_stack,
p_emit_expr);
return;
}
case exprstatetype::expect_type:
case exprstatetype::expect_symbol:
/* unreachable
* (this exprstate issues pop instruction from exprstate::on_input()
*/
assert(false);
return;
case exprstatetype::expr_progress:
/* unreachable */
assert(false);
return;
case exprstatetype::invalid:
case exprstatetype::n_exprstatetype:
/* unreachable */
assert(false);
return;
}
assert(false);
} /*on_expr*/
void