ref: 5196e4c16239a9f593c4efa14819b70721006740
parent: 9193bdc08bcba1b515fb60d25b700963a454b90a
author: Ori Bernstein <[email protected]>
date: Thu Aug 16 16:40:56 EDT 2012
We declare the variables in pattern matches now.
We used to just error on unbound variables. Now we recognize
that we need to match them, and declare a variable for them.
We just don't actually assign it what we should...
--- a/parse/infer.c
+++ b/parse/infer.c
@@ -14,7 +14,6 @@
typedef struct Inferstate Inferstate;
struct Inferstate {- int inpat;
int ingeneric;
int sawret;
Type *ret;
@@ -45,6 +44,46 @@
static Type *unify(Inferstate *st, Node *ctx, Type *a, Type *b);
static Type *tf(Inferstate *st, Type *t);
+/* Tries to give a good string describing the context
+ * for the sake of error messages. */
+static char *ctxstr(Inferstate *st, Node *n)
+{+ char *s;
+ char *t;
+ char *u;
+ char buf[512];
+
+ switch (n->type) {+ default:
+ s = nodestr(n->type);
+ break;
+ case Ndecl:
+ u = declname(n);
+ t = tystr(tf(st, decltype(n)));
+ snprintf(buf, 512, "%s:%s", u, t);
+ s = strdup(buf);
+ free(t);
+ break;
+ case Nname:
+ s = namestr(n);
+ break;
+ case Nexpr:
+ if (exprop(n) == Ovar)
+ u = namestr(n->expr.args[0]);
+ else
+ u = opstr(exprop(n));
+ if (exprtype(n))
+ t = tystr(tf(st, exprtype(n)));
+ else
+ t = strdup("unknown");+ snprintf(buf, 512, "%s:%s", u, t);
+ s = strdup(buf);
+ free(t);
+ break;
+ }
+ return s;
+}
+
/* Set a scope's enclosing scope up correctly.
* We don't do this in the parser for some reason. */
static void setsuper(Stab *st, Stab *super)
@@ -269,44 +308,20 @@
return tf(st, t);
}
-/* Tries to give a good string describing the context
- * for the sake of error messages. */
-static char *ctxstr(Inferstate *st, Node *n)
+static Ucon *uconresolve(Inferstate *st, Node *n)
{- char *s;
- char *t;
- char *u;
- char buf[512];
+ Ucon *uc;
+ Node **args;
- switch (n->type) {- default:
- s = nodestr(n->type);
- break;
- case Ndecl:
- u = declname(n);
- t = tystr(tf(st, decltype(n)));
- snprintf(buf, 512, "%s:%s", u, t);
- s = strdup(buf);
- free(t);
- break;
- case Nname:
- s = namestr(n);
- break;
- case Nexpr:
- if (exprop(n) == Ovar)
- u = namestr(n->expr.args[0]);
- else
- u = opstr(exprop(n));
- if (exprtype(n))
- t = tystr(tf(st, exprtype(n)));
- else
- t = strdup("unknown");- snprintf(buf, 512, "%s:%s", u, t);
- s = strdup(buf);
- free(t);
- break;
- }
- return s;
+ args = n->expr.args;
+ uc = getucon(curstab(), args[0]);
+ if (!uc)
+ fatal(n->line, "No union constructor %s", ctxstr(st, args[0]));
+ if (!uc->etype && n->expr.nargs > 1)
+ fatal(n->line, "nullary union constructor %s passed arg ", ctxstr(st, args[0]));
+ else if (uc->etype && n->expr.nargs != 2)
+ fatal(n->line, "union constructor %s needs arg ", ctxstr(st, args[0]));
+ return uc;
}
/* Binds the type parameters present in the
@@ -647,6 +662,67 @@
settype(st, n, mktyarray(n->line, type(st, n->lit.seqval[0]), mkintlit(n->line, n->lit.nelt)));
}
+static void inferpat(Inferstate *st, Node *n, Node ***bind, size_t *nbind)
+{+ size_t i;
+ Ucon *uc;
+ Node **args;
+ Node *s;
+ Type *t;
+
+ args = n->expr.args;
+ for (i = 0; i < n->expr.nargs; i++)
+ if (args[i]->type == Nexpr)
+ inferpat(st, args[i], bind, nbind);
+ switch (exprop(n)) {+ case Ocons:
+ uc = uconresolve(st, n);
+ if (uc->etype)
+ unify(st, n, uc->etype, type(st, args[1]));
+ settype(st, n, uc->utype);
+ break;
+ case Ovar:
+ s = getdcl(curstab(), args[0]);
+ if (s) {+ if (s->decl.isgeneric)
+ t = freshen(st, s->decl.type);
+ else if (s->decl.isconst)
+ t = s->decl.type;
+ else
+ fatal(n->line, "Can't match against variables in nterns near %s", ctxstr(st, n));
+ } else {+ t = mktyvar(n->line);
+ s = mkdecl(n->line, n->expr.args[0], t);
+ settype(st, n, t);
+ lappend(bind, nbind, s);
+ }
+ settype(st, n, t);
+ n->expr.did = s->decl.did;
+ break;
+ case Olit:
+ infernode(st, n, NULL, NULL);
+ break;
+ case Omemb:
+ infernode(st, n, NULL, NULL);
+ break;
+ default:
+ die("Bad pattern to match against");+ break;
+ }
+}
+
+void addbindings(Inferstate *st, Node *n, Node **bind, size_t nbind)
+{+ size_t i;
+
+ /* order of binding shouldn't matter, so push them into the block
+ * in reverse order. */
+ for (i = 0; i < nbind; i++) {+ putdcl(n->block.scope, bind[i]);
+ linsert(&n->block.stmts, &n->block.nstmts, 0, bind[i]);
+ }
+}
+
static void inferexpr(Inferstate *st, Node *n, Type *ret, int *sawret)
{Node **args;
@@ -793,14 +869,8 @@
}
break;
case Ocons:
- uc = getucon(curstab(), args[0]);
- if (!uc)
- fatal(n->line, "No union constructor %s", ctxstr(st, args[0]));
- if (!uc->etype && n->expr.nargs > 1)
- fatal(n->line, "nullary union constructor %s passed arg ", ctxstr(st, args[0]));
- else if (uc->etype && n->expr.nargs != 2)
- fatal(n->line, "union constructor %s needs arg ", ctxstr(st, args[0]));
- else if (uc->etype)
+ uc = uconresolve(st, n);
+ if (uc->etype)
unify(st, n, uc->etype, type(st, args[1]));
settype(st, n, uc->utype);
break;
@@ -882,6 +952,8 @@
size_t i;
Node *d;
Node *s;
+ size_t nbound;
+ Node **bound;
if (!n)
return;
@@ -949,9 +1021,10 @@
}
break;
case Nmatch:
- st->inpat++;
- infernode(st, n->match.pat, NULL, sawret);
- st->inpat--;
+ bound = NULL;
+ nbound = 0;
+ inferpat(st, n->match.pat, &bound, &nbound);
+ addbindings(st, n->match.block, bound, nbound);
infernode(st, n->match.block, ret, sawret);
break;
case Nexpr: