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xo-reader2 xo-expresion2: work on define-expressions [WIP]

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This commit is contained in:
Roland Conybeare 2026-01-19 21:25:30 -05:00
commit 19b6caa89d
23 changed files with 263 additions and 67 deletions
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69
src/reader2/DDefineSsm.cpp
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@ -1,9 +1,10 @@
/** @file DDefineSsm.cpp
/** @file DDefineSsm.cpp
*
* @author Roland Conybeare, Jan 2026
**/
#include "DDefineSsm.hpp"
#include "DExpectSymbolSsm.hpp"
#include "ssm/ISyntaxStateMachine_DDefineSsm.hpp"
#ifdef NOT_YET
@ -328,28 +329,33 @@ namespace xo {
////////////////////////////////////////////////////////////////
DDefineSsm::DDefineSsm()
: defstate_{defexprstatetype::def_0}
DDefineSsm::DDefineSsm(DDefineExpr * def_expr)
: defstate_{defexprstatetype::def_0},
def_expr_{def_expr}
{}
DDefineSsm *
DDefineSsm::make(DArena & mm)
DDefineSsm::make(DArena & mm,
DDefineExpr * def_expr)
{
void * mem = mm.alloc(typeseq::id<DDefineSsm>(),
sizeof(DDefineSsm));
return new (mem) DDefineSsm();
return new (mem) DDefineSsm(def_expr);
}
void
DDefineSsm::start(DArena & mm,
obj<AAllocator> expr_mm,
ParserStateMachine * p_psm)
{
//scope log(XO_DEBUG(p_psm->debug_flag()));
assert(p_psm->stack());
DDefineSsm * define_ssm = DDefineSsm::make(mm);
DDefineExpr * def_expr = DDefineExpr::make_empty(expr_mm);
DDefineSsm * define_ssm = DDefineSsm::make(mm, def_expr);
obj<ASyntaxStateMachine> ssm
= with_facet<ASyntaxStateMachine>::mkobj(define_ssm);
@ -387,7 +393,7 @@ namespace xo {
case defexprstatetype::def_0:
case defexprstatetype::n_defexprstatetype:
assert(false); // impossible
return nullptr;
return "impossible!?";
case defexprstatetype::def_1:
return "symbol";
case defexprstatetype::def_2:
@ -409,11 +415,57 @@ namespace xo {
DDefineSsm::on_parsed_symbol(std::string_view sym,
ParserStateMachine * p_psm)
{
if (this->defstate_ == defexprstatetype::def_1) {
this->defstate_ = defexprstatetype::def_2;
def_expr_.data()->assign_lhs_name(sym);
// if this is a genuine top-level define (i.e. nesting level = 0),
// then we need to upsert so we can refer to rhs later.
//
// In other contexts (e.g. body-of-lambda) will be rewriting
// {
// def y = foo(x,x);
// bar(y,y);
// }
// into something like
// {
// (lambda (y123) bar(y123,y123))(foo(x,x));
// }
//
// This works in the body of lambda, because we don't evaluate anything
// until lambda definition is complete.
//
// For interactive top-level defs we want to evaluate as we go,
// so need incremental bindings.
if (p_psm->is_at_toplevel()) {
/** remember variable binding in current lexical context **/
p_psm->upsert_var(def_expr_.data()->lhs());
}
return;
}
p_psm->illegal_input_on_symbol("DDefineSsm::on_parsed_symbol",
sym,
this->get_expect_str());
}
void
DDefineSsm::on_symbol_token(const Token & tk,
ParserStateMachine * p_psm)
{
// note:
// in state def_1, DDefineSsm learns symbol via .on_parsed_symbol().
// symbol token arriving here means encountered symbol while
// in some other, which can't happen for valid Schematika input
p_psm->illegal_input_on_token("DDefineSssm::on_symbol_token",
tk,
this->get_expect_str());
}
void
DDefineSsm::on_def_token(const Token & tk,
ParserStateMachine * p_psm)
@ -421,7 +473,8 @@ namespace xo {
if (this->defstate_ == defexprstatetype::def_0) {
this->defstate_ = defexprstatetype::def_1;
// expect_symbol_xs::start(p_psm->parser_alloc(), p_psm);
DExpectSymbolSsm::start(p_psm->parser_alloc(), p_psm);
return;
}
p_psm->illegal_input_on_token("DDefineSsm::on_define_token",