roland/xo-alloc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

xo-reader: streamline: simplify expect_expr_xs

Browse source
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
Download patch file Download diff file Expand all files Collapse all files

10
include/xo/reader/expect_expr_xs.hpp
View file

@ -22,10 +22,20 @@ namespace xo {
virtual void on_leftparen_token(const token_type & tk,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr) override;
virtual void on_symbol_token(const token_type & tk,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr) override;
virtual void on_f64_token(const token_type & tk,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr) override;
/** update exprstate in response to a successfully-parsed subexpression **/
virtual void on_expr(ref::brw<Expression> expr,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr) override;
private:
};

6
include/xo/reader/exprstate.hpp
View file

@ -87,12 +87,6 @@ namespace xo {
virtual bool admits_semicolon() const;
/** true iff this parsing state admits a singleassign '=' as next token **/
virtual bool admits_singleassign() const;
#ifdef OBSOLETE
/** true iff this parsing state admits a leftparen '(' as next token **/
virtual bool admits_leftparen() const;
/** truee iff this parsing state admits a rightparen ')' as next token **/
virtual bool admits_rightparen() const;
#endif
/** update exprstate in response to incoming token @p tk,
* forward instructions to parent parser

53
src/reader/expect_expr_xs.cpp
View file

@ -38,6 +38,41 @@ namespace xo {
p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
}
void
expect_expr_xs::on_symbol_token(const token_type & /*tk*/,
exprstatestack * /*p_stack*/,
rp<Expression> * /*p_emit_expr*/)
{
/* todo: treat symbol as variable name */
/* 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;
}
void
expect_expr_xs::on_f64_token(const token_type & tk,
exprstatestack * p_stack,
@ -57,6 +92,24 @@ namespace xo {
(Constant<double>::make(tk.f64_value())));
}
void
expect_expr_xs::on_expr(ref::brw<Expression> expr,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr)
{
constexpr bool c_debug_flag = true;
scope log(XO_DEBUG(c_debug_flag));
log && log(xtag("exstype", this->exs_type_),
xtag("expr", expr));
std::unique_ptr<exprstate> self = p_stack->pop_exprstate();
p_stack->top_exprstate().on_expr(expr,
p_stack,
p_emit_expr);
} /*on_expr*/
} /*namespace scm*/
} /*namespace xo*/

112
src/reader/exprstate.cpp
View file

@ -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