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authorKaz Kylheku <kaz@kylheku.com>2020-08-17 21:38:13 -0700
committerKaz Kylheku <kaz@kylheku.com>2020-08-17 21:38:13 -0700
commit8f03981dfcd66aed76a98716e1a41a8bf1f0dbe6 (patch)
treed10f3588a0b1de6c6d1addcf0987904141cd5d78
parent42ba138efa6159e1d0387b8f3c7b3fb1a34721ad (diff)
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txr: identify output repeat vars at parse time
Up to now the @(repeat) and @(rep) directives have scanned their interior to find output variables. We now hoist that into the parser; the variables are found up-front and integrated into the abstract syntax. This work anticipates doing a more proper job of identifying free variables in Lisp expressions. * match.c (extract_vars): Delete static this function here. It moves into parser.y. (extract_bindings): Don't call extract_vars to obtain the variables occurring in the repeat body. Get it as a new argument, occur_vars. (do_output_line, do_repeat): Extract the new occur_vars element of the abstract syntax node and pass it to extract_bindings. * parser.y (extract_vars): New static function, moved here from match.c. (repeat_rep_helper): Scan over each of the repeat subclauses with extract vars. Catenate the resulting lists together and pass through uniq to squash repeated symbols. Then add the resulting vars as a new element of the returned syntax node.
-rw-r--r--match.c58
-rw-r--r--parser.y58
2 files changed, 64 insertions, 52 deletions
diff --git a/match.c b/match.c
index 0e03f93f..c2ac517b 100644
--- a/match.c
+++ b/match.c
@@ -1886,59 +1886,13 @@ static val bind_cdr(val bind_cons)
bind_cons);
}
-static val extract_vars(val output_spec)
-{
- list_collect_decl (vars, tai);
-
- if (consp(output_spec)) {
- val sym = first(output_spec);
- if (sym == var_s) {
- val name = second(output_spec);
- val modifiers = third(output_spec);
-
- if (bindable(name))
- tai = list_collect(tai, name);
- else
- tai = list_collect_nconc(tai, extract_vars(name));
-
- for (; modifiers; modifiers = cdr(modifiers)) {
- val mod = car(modifiers);
- if (bindable(mod)) {
- tai = list_collect(tai, mod);
- } else if (consp(mod)) {
- val msym = car(mod);
-
- if (msym == dwim_s) {
- val arg = second(mod);
-
- if (bindable(arg)) {
- tai = list_collect(tai, arg);
- } else if (consp(arg) && car(arg) == rcons_s) {
- val f = second(arg);
- val t = third(arg);
- if (bindable(f))
- tai = list_collect(tai, f);
- if (bindable(t))
- tai = list_collect(tai, t);
- }
- }
- }
- }
- } else if (sym != expr_s) {
- for (; output_spec; output_spec = cdr(output_spec))
- tai = list_collect_nconc(tai, extract_vars(car(output_spec)));
- }
- }
-
- return vars;
-}
-
-static val extract_bindings(val bindings, val output_spec, val vars)
+static val extract_bindings(val bindings, val output_spec,
+ val vars, val occur_vars)
{
list_collect_decl (bindings_out, ptail);
list_collect_decl (var_list, vtail);
- vtail = list_collect_nconc(vtail, extract_vars(output_spec));
+ vtail = list_collect_nconc(vtail, occur_vars);
for (; vars; vars = cdr(vars)) {
val var = car(vars);
@@ -2007,6 +1961,7 @@ static void do_output_line(val bindings, val specline, val filter, val out)
val empty_clauses = pop(&clauses);
val mod_clauses = pop(&clauses);
val modlast_clauses = pop(&clauses);
+ val occur_vars = pop(&clauses);
val counter_spec = getplist(args, counter_k);
val consp_counter = consp(counter_spec);
val counter = if3(consp_counter, first(counter_spec), counter_spec);
@@ -2015,7 +1970,7 @@ static void do_output_line(val bindings, val specline, val filter, val out)
second(counter_spec),
bindings), zero);
val vars = getplist(args, vars_k);
- val bind_cp = extract_bindings(bindings, elem, vars);
+ val bind_cp = extract_bindings(bindings, elem, vars, occur_vars);
val max_depth = reduce_left(func_n2(max2),
bind_cp, zero,
chain(func_n1(cdr),
@@ -2142,6 +2097,7 @@ static void do_repeat(val bindings, val repeat_syntax, val filter, val out)
val empty_clauses = pop(&clauses);
val mod_clauses = pop(&clauses);
val modlast_clauses = pop(&clauses);
+ val occur_vars = pop(&clauses);
val counter_spec = getplist(args, counter_k);
val consp_counter = consp(counter_spec);
val counter = if3(consp_counter, first(counter_spec), counter_spec);
@@ -2150,7 +2106,7 @@ static void do_repeat(val bindings, val repeat_syntax, val filter, val out)
second(counter_spec),
bindings), zero);
val vars = getplist(args, vars_k);
- val bind_cp = extract_bindings(bindings, repeat_syntax, vars);
+ val bind_cp = extract_bindings(bindings, repeat_syntax, vars, occur_vars);
val max_depth = reduce_left(func_n2(max2),
bind_cp, zero,
chain(func_n1(cdr),
diff --git a/parser.y b/parser.y
index 97c8f020..d829b4f7 100644
--- a/parser.y
+++ b/parser.y
@@ -1481,6 +1481,53 @@ static val expand_repeat_rep_args(val args)
return out;
}
+static val extract_vars(val output_spec)
+{
+ list_collect_decl (vars, tai);
+
+ if (consp(output_spec)) {
+ val sym = first(output_spec);
+ if (sym == var_s) {
+ val name = second(output_spec);
+ val modifiers = third(output_spec);
+
+ if (bindable(name))
+ tai = list_collect(tai, name);
+ else
+ tai = list_collect_nconc(tai, extract_vars(name));
+
+ for (; modifiers; modifiers = cdr(modifiers)) {
+ val mod = car(modifiers);
+ if (bindable(mod)) {
+ tai = list_collect(tai, mod);
+ } else if (consp(mod)) {
+ val msym = car(mod);
+
+ if (msym == dwim_s) {
+ val arg = second(mod);
+
+ if (bindable(arg)) {
+ tai = list_collect(tai, arg);
+ } else if (consp(arg) && car(arg) == rcons_s) {
+ val f = second(arg);
+ val t = third(arg);
+ if (bindable(f))
+ tai = list_collect(tai, f);
+ if (bindable(t))
+ tai = list_collect(tai, t);
+ }
+ }
+ }
+ }
+ } else if (sym != expr_s) {
+ for (; output_spec; output_spec = cdr(output_spec))
+ tai = list_collect_nconc(tai, extract_vars(car(output_spec)));
+ }
+ }
+
+ return vars;
+}
+
static val repeat_rep_helper(val sym, val args, val main, val parts)
{
uses_or2;
@@ -1491,6 +1538,7 @@ static val repeat_rep_helper(val sym, val args, val main, val parts)
val empty_parts = nil, empty_parts_p = nil;
val mod_parts = nil, mod_parts_p = nil;
val modlast_parts = nil, modlast_parts_p = nil;
+ val occur_vars = nil;
val iter;
for (iter = parts; iter != nil; iter = cdr(iter)) {
@@ -1528,9 +1576,17 @@ static val repeat_rep_helper(val sym, val args, val main, val parts)
mod_parts = or2(nreverse(mod_parts), mod_parts_p);
modlast_parts = or2(nreverse(modlast_parts), modlast_parts_p);
+ occur_vars = extract_vars(main);
+ occur_vars = nappend2(occur_vars, extract_vars(single_parts));
+ occur_vars = nappend2(occur_vars, extract_vars(first_parts));
+ occur_vars = nappend2(occur_vars, extract_vars(last_parts));
+ occur_vars = nappend2(occur_vars, extract_vars(empty_parts));
+ occur_vars = nappend2(occur_vars, extract_vars(mod_parts));
+ occur_vars = uniq(occur_vars);
+
return list(sym, exp_args, main, single_parts, first_parts,
last_parts, empty_parts, nreverse(mod_parts),
- nreverse(modlast_parts), nao);
+ nreverse(modlast_parts), occur_vars, nao);
}
static void process_catch_exprs(val exprs)