From df9f85b3b720a9ebf7381b2cad7a9680ad0e31bf Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sat, 26 Nov 2016 08:40:22 -0800
Subject: bugfix: quasilit read/print consistency, part 1.
The bug is that `@@@a` prints as `@@a` which
reads as a different object.
In this patch we simplify how quasiliterals are represented.
Embedded expressions are no longer (sys:expr E), just E.
Meta-numbers N and variables V are still (sys:var N).
However `@@a` and `@a` remain equivalent.
* eval.c (subst_vars): No need to look for expr_s;
just evaluate a compound form. The recursive nested
case is unnecessary and is removed.
(expand_quasi): Do nothandle expr_s; it is not
part of the quasi syntax any more.
* lib.c (out_quasi_str): Do not look for expr_s in the
quasi syntax; just print any expression with a @
the fallback case.
* match.c (tx_subst_vars): Analogous changes to those
done in subst_vars in eval.c.
* parser.y (quasi_meta_helper): Static function removed.
This was responsible for the issue due to stripping a
level of meta from expressions already having a meta
on them.
(quasi_item): In the `@` n_expr syntax case, no longer
call quasi_meta_helper. The remaining logic is simple
enough to put in line. Symbols and integers get wrapped
with (sys:var ...); other expressions are integrated
into the syntax as-is.
---
eval.c | 15 +++------------
lib.c | 4 ++--
match.c | 11 +++--------
parser.y | 25 +++++--------------------
4 files changed, 13 insertions(+), 42 deletions(-)
diff --git a/eval.c b/eval.c
index a5f74b5a..6fe12132 100644
--- a/eval.c
+++ b/eval.c
@@ -2365,19 +2365,14 @@ val subst_vars(val forms, val env, val filter)
iter = list_collect_append(iter, nested);
forms = cdr(forms);
continue;
- } else if (sym == expr_s) {
- val str = eval(rest(form), env, form);
+ } else {
+ val str = eval(form, env, form);
if (listp(str))
str = cat_str(mapcar(func_n1(tostringp), str), lit(" "));
else if (!stringp(str))
str = tostringp(str);
forms = cons(filter_string_tree(filter, tostringp(str)), rest(forms));
continue;
- } else {
- val nested = subst_vars(form, env, filter);
- iter = list_collect_append(iter, nested);
- forms = cdr(forms);
- continue;
}
} else if (bindable(form)) {
forms = cons(cons(var_s, cons(form, nil)), cdr(forms));
@@ -2983,12 +2978,8 @@ static val expand_quasi(val quasi_forms, val menv)
if (consp(form)) {
val sym = car(form);
- if (sym == expr_s) {
- val expr_ex = expand(rest(form), menv);
- if (expr_ex != rest(form))
- form_ex = rlcp(cons(sym, expr_ex), form);
- } else if (sym == var_s) {
+ if (sym == var_s) {
val param = second(form);
val mods = third(form);
val param_ex = expand(param, menv);
diff --git a/lib.c b/lib.c
index 641b7337..c510ba73 100644
--- a/lib.c
+++ b/lib.c
@@ -9481,9 +9481,9 @@ static void out_quasi_str(val args, val out, struct strm_ctx *ctx)
}
if (need_brace)
put_char(chr('}'), out);
- } else if (sym == expr_s) {
+ } else {
put_char(chr('@'), out);
- obj_print_impl(rest(elem), out, nil, ctx);
+ obj_print_impl(elem, out, nil, ctx);
}
} else {
obj_print_impl(elem, out, nil, ctx);
diff --git a/match.c b/match.c
index d9df8764..93b84a07 100644
--- a/match.c
+++ b/match.c
@@ -1493,13 +1493,13 @@ static val tx_subst_vars(val spec, val bindings, val filter)
iter = list_collect_append(iter, nested);
spec = cdr(spec);
continue;
- } else if (sym == expr_s) {
+ } else {
if (opt_compat && opt_compat < 100) {
- val result = tleval(spec, rest(elem), bindings);
+ val result = tleval(spec, elem, bindings);
spec = cons(filter_string_tree(filter, tostringp(result)), rest(spec));
continue;
} else {
- val str = tleval(spec, rest(elem), bindings);
+ val str = tleval(spec, elem, bindings);
if (listp(str))
str = cat_str(mapcar(func_n1(tostringp), str), lit(" "));
else if (!stringp(str))
@@ -1507,11 +1507,6 @@ static val tx_subst_vars(val spec, val bindings, val filter)
spec = cons(filter_string_tree(filter, tostringp(str)), rest(spec));
continue;
}
- } else {
- val nested = tx_subst_vars(elem, bindings, filter);
- iter = list_collect_append(iter, nested);
- spec = cdr(spec);
- continue;
}
}
diff --git a/parser.y b/parser.y
index 8d3e5a89..b54c7bf8 100644
--- a/parser.y
+++ b/parser.y
@@ -68,7 +68,6 @@ static val rlrec(parser_t *, val form, val line);
static wchar_t char_from_name(const wchar_t *name);
static val make_expr(parser_t *, val sym, val rest, val lineno);
static val check_for_include(val spec_rev);
-static val quasi_meta_helper(val obj);
static void misplaced_consing_dot_check(scanner_t *scanner, val term_atom_cons);
#if YYBISON
@@ -1165,7 +1164,11 @@ quasi_item : litchars { $$ = lit_char_helper($1); }
| q_var { $$ = $1; }
| METANUM { $$ = cons(var_s, cons($1, nil));
rl($$, num(parser->lineno)); }
- | '@' n_expr { $$ = quasi_meta_helper($2); }
+ | '@' n_expr { if (integerp($2) || symbolp($2))
+ $$ = rlcp_tree(cons(var_s, cons($2, nil)),
+ $2);
+ else
+ $$ = $2; }
;
litchars : LITCHAR { $$ = rl(cons(chr($1), nil), num(parser->lineno)); }
@@ -1644,24 +1647,6 @@ static val check_for_include(val spec_rev)
return spec_rev;
}
-static val quasi_meta_helper(val obj)
-{
- if (integerp(obj) || symbolp(obj))
- goto var;
-
- if (atom(obj))
- goto expr;
-
- if (first(obj) == var_s || first(obj) == expr_s)
- return obj;
-
-expr:
- return rlcp(cons(expr_s, obj), obj);
-
-var:
- return rlcp_tree(cons(var_s, cons(obj, nil)), obj);
-}
-
static void misplaced_consing_dot_check(scanner_t *scanner, val term_atom_cons)
{
if (car(term_atom_cons) != unique_s) {
--
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