break & continue

1 files changed, 65 insertions, 6 deletions

diff --git a/bootstrap/parse.c b/bootstrap/parse.c
index 02980cc..631d007 100644
--- a/bootstrap/parse.c
+++ b/bootstrap/parse.c
@@ -373,6 +373,9 @@ lex(struct parser *P) {
          tok.t = '#len';
       } else if (!strcmp(s, "#?")) {
          tok.t = '#?';
+      } else if (!strncmp(s, "#:", 2)) {
+         tok.t = TKlabel;
+         tok.str = xstrdup(s);
       } else {
          fatal(P, P->tokspan, "invalid #keyword");
       } 
@@ -1860,7 +1863,7 @@ pstforletyield(struct stmt *st, void *arg) {
 }
 
 static struct stmt
-pstfor(struct parser *P) {
+pstfor(struct parser *P, const char *label) {
    struct stmt st = {Sfor};
    struct tok tok;
 
@@ -1895,7 +1898,16 @@ pstfor(struct parser *P) {
       st.loop.next = exprdup(parseexpr(P));
       lexexpect(P, '{');
    }
-   st.loop.body = parseblock(P).block;
+   st.loop.id = P->loopid++;
+   struct env env = {P->curenv};
+   if (label) {
+      pushenv(P, &env);
+      putdecl(P, tok.span, &(struct decl) { Dlabel, label, .loopid = st.loop.id });
+   }
+   WITH_TMPCHANGE(int, P->curloop, st.loop.id)
+      st.loop.body = parseblock(P).block;
+   if (label)
+      popenv(P);
    return st;
 }
 
@@ -2158,6 +2170,7 @@ static void
 parsestmt(stmt_yielder_t yield, void *yarg, struct parser *P) {
    struct stmt st = {0};
    struct tok tok;
+   const char *label = NULL;
 
    if (lexmatch(P, &tok, '{')) {
       st.span = tok.span;
@@ -2168,7 +2181,16 @@ parsestmt(stmt_yielder_t yield, void *yarg, struct parser *P) {
    } else if (lexmatch(P, &tok, TKkw_if)) {
       st.span = tok.span;
       st = pstifelse(P);
+   } else if (lexmatch(P, &tok, TKlabel)) {
+      label = tok.str;
+      if (lexmatch(P, &tok, TKkw_while))
+         goto whilel;
+      else if (lexmatch(P, &tok, TKkw_for))
+         goto forl;
+      else
+         fatal(P, tok.span, "cannot use label for this statement");
    } else if (lexmatch(P, &tok, TKkw_while)) {
+   whilel:
       st.t = Swhile;
       st.span = tok.span;
       st.loop.test = parseexpr(P);
@@ -2177,10 +2199,20 @@ parsestmt(stmt_yielder_t yield, void *yarg, struct parser *P) {
                "while statement condition must be bool or pointer (%t)",
                st.loop.test.ty);
       lexexpect(P, '{');
-      st.loop.body = parseblock(P).block;
+      st.loop.id = P->loopid++;
+      struct env env = { P->curenv };
+      if (label) {
+         pushenv(P, &env);
+         putdecl(P, tok.span, &(struct decl) { Dlabel, label, .loopid = st.loop.id });
+      }
+      WITH_TMPCHANGE(int, P->curloop, st.loop.id)
+         st.loop.body = parseblock(P).block;
+      if (label)
+         popenv(P);
    } else if (lexmatch(P, &tok, TKkw_for)) {
+   forl:
       st.span = tok.span;
-      st = pstfor(P);
+      st = pstfor(P, label);
    } else if (lexmatch(P, &tok, TKkw_switch)) {
       st = pstswitch(P);
       st.span = tok.span;
@@ -2201,6 +2233,32 @@ parsestmt(stmt_yielder_t yield, void *yarg, struct parser *P) {
          fatal(P, tok.span,
                "return statement in non-void function must return a value");
       }
+   } else if (lexmatch(P, &tok, TKkw_break)) {
+      if (P->curloop < 0)
+         fatal(P, tok.span, "break outside loop");
+      st.t = Sbreak;
+      st.brkcon.id = P->curloop;
+      if (lexmatch(P, &tok, TKlabel)) {
+         const struct decl *decl = finddecl(P, tok.str);
+         if (!decl)
+            fatal(P, tok.span, "no such label %T", tok);
+         assert(decl->t == Dlabel);
+         st.brkcon.id = decl->loopid;
+      }
+      lexexpect(P, ';');
+   } else if (lexmatch(P, &tok, TKkw_continue)) {
+      if (P->curloop < 0)
+         fatal(P, tok.span, "continue outside loop");
+      st.t = Scontinue;
+      st.brkcon.id = P->curloop;
+      if (lexmatch(P, &tok, TKlabel)) {
+         const struct decl *decl = finddecl(P, tok.str);
+         if (!decl)
+            fatal(P, tok.span, "no such label %T", tok);
+         assert(decl->t == Dlabel);
+         st.brkcon.id = decl->loopid;
+      }
+      lexexpect(P, ';');
    } else if (isdecltokt((tok = lexpeek(P)).t)) {
       st.t = Sdecl;
       st.span = tok.span;
@@ -2327,8 +2385,9 @@ parsefn(struct decl *decl, struct parser *P) {
             putdecl(P, tok.span, &decl);
          }
          fn->body = xcalloc(1, sizeof *fn->body);
-         WITH_TMPCHANGE(int, P->varid, 0)
-            *fn->body = parseblock(P);
+         WITH_TMPCHANGE(int, P->curloop, -1) WITH_TMPCHANGE(int, P->loopid, 0)
+            WITH_TMPCHANGE(int, P->varid, 0)
+               *fn->body = parseblock(P);
          popenv(P);
       }
    }