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xo-reader: handle sequence with embedded local vars

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This commit is contained in:
Roland Conybeare 2024-08-23 10:52:51 -04:00
commit 7fad60290d
5 changed files with 225 additions and 8 deletions
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44
src/reader/sequence_xs.cpp
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@ -3,10 +3,12 @@
#include "sequence_xs.hpp"
#include "parserstatemachine.hpp"
#include "expect_expr_xs.hpp"
#include "let1_xs.hpp"
#include "xo/expression/DefineExpr.hpp"
#include "xo/expression/Sequence.hpp"
namespace xo {
using xo::ast::Sequence;
using xo::ast::DefineExpr;
namespace scm {
std::unique_ptr<sequence_xs>
@ -42,19 +44,47 @@ namespace xo {
*
* becomes:
*
* /-- .outer_seq_expr_
* v
* Sequence(
* ...prefix,
* Apply(Lambda(gen999, [Variable(lhs_name, type(rhs))], sequencify(rest...)),
*
* /-- .inner_lm_expr_
* v
* Apply(Lambda(gen999,
* [Variable(lhs_name, type(rhs))],
* /-- .expr_v_
* v
* sequencify(rest...)),
* rhs))
*
* so amongst other things,
* helpful to have nested seequence_xs that propagates '}' instead of swallowing it.
* helpful to have nested seequence_xs that propagates '}'
* instead of swallowing it.
*/
ref::brw<DefineExpr> def_expr = DefineExpr::from(expr);
this->expr_v_.push_back(expr.promote());
expect_expr_xs::start(true /*allow_defs*/,
true /*cxl_on_rightbrace*/,
p_psm);
if (def_expr) {
/** nested_start: control returns via
* .on_expr(x)
* with x something like:
* Apply(Lambda(gensym(),
* [Variable(def_expr->lhs_name(),
* def_expr->valuetype())],
* body...))
* followed immediately by
* .on_rightbrace_token()
**/
let1_xs::start(def_expr->lhs_name(),
def_expr->rhs(),
p_psm);
} else {
this->expr_v_.push_back(expr.promote());
expect_expr_xs::start(true /*allow_defs*/,
true /*cxl_on_rightbrace*/,
p_psm);
}
}
void