Introduce 'function' built-in

As requested in #4, here's my proposal. This is a wrapper around goto and source. The script recurses itself and searches for a goto label. It's an error for labels not contain an exit to their end. Function calls outside labels are, by default, labeled main.

This was tested sparsely, and may contain bugs I haven't faced, but is working as expected. One bug to be noted is that pipes don't give up on errors. This is possibly due to forking.

I noticed Tcsh has a built-in function command, but I can't trace the code. Said built-in function command is evaluated before mine, thus those who attempt to execute it won't get the correct error message.

sh.c

@@ -111,6 +111,7 @@ int exitset = 0;
 static time_t chktim; /* Time mail last checked */
 char *progname;
 int tcsh;
+struct funcargs *fargv = NULL;
 
 /*
  * This preserves the input state of the shell. It is used by
@@ -1995,6 +1996,59 @@ process(int catch)
 
  getexit(osetexit);
  omark = cleanup_push_mark();
+
+ /* If this is a function, setup STRargv and invoke goto. */
+ if (fargv) {
+ int funcdelim = 0;
+ Char funcexit[] = { 'e', 'x', 'i', 't', 0 },
+ funcmain[] = { 'm', 'a', 'i', 'n', 0 };
+ struct Strbuf aword = Strbuf_INIT;
+ cleanup_push(&aword, Strbuf_cleanup);
+ Sgoal = funcmain;
+ Stype = TC_GOTO;
+
+ if (!fargv->prev)
+ while (!funcdelim) {
+ (void) getword(&aword);
+ Strbuf_terminate(&aword);
+
+ if (aword.s[0] != ':' && lastchr(aword.s) == ':')
+ funcerror(funcmain, funcexit);
+ else if (eq(aword.s, funcexit))
+ funcdelim = 1;
+
+ (void) getword(NULL);
+ }
+
+ setq(STRargv, &fargv->v[3], &shvhed, 0);
+ dogoto(&fargv->v[1], fargv->t);
+
+ {
+ struct Ain a;
+
+ cleanup_push(&aword, Strbuf_cleanup);
+ Sgoal = fargv->v[2];
+ Stype = TC_EXIT;
+ a.type = TCSH_F_SEEK;
+ btell(&a);
+ funcdelim = 0;
+
+ while (!funcdelim) {
+ (void) getword(&aword);
+ Strbuf_terminate(&aword);
+
+ if (aword.s[0] != ':' && lastchr(aword.s) == ':')
+ funcerror(fargv->v[2], funcexit);
+ else if (eq(aword.s, funcexit))
+ funcdelim = 1;
+
+ (void) getword(NULL);
+ }
+
+ bseek(&a);
+ }
+ }
+
  for (;;) {
  struct command *t;
  int hadhist, old_pintr_disabled;
@@ -2179,6 +2233,20 @@ process(int catch)
  else
  haderr = 1;
  }
+
+ if (fargv) {
+ /* Reset STRargv on function exit. */
+ setv(STRargv, NULL, 0);
+
+ if (fargv->prev)
+ {
+ fargv = fargv->prev;
+ free(fargv->next);
+ }
+ else
+ free(fargv);
+ }
+
  cleanup_pop_mark(omark);
  resexit(osetexit);
  exitset--;

sh.decls.h

@@ -105,6 +105,7 @@ extern void xfree_indirect(void *);
 extern void errinit (void);
 extern void seterror (unsigned int, ...);
 extern void fixerror (void);
+extern void funcerror (Char *, Char *);
 extern void stderror (unsigned int, ...)
  __attribute__((__noreturn__));
 
@@ -150,6 +151,7 @@ extern void doend (Char **, struct command *);
 extern void doeval (Char **, struct command *);
 extern void doexit (Char **, struct command *);
 extern void doforeach (Char **, struct command *);
+extern void dofunction (Char **, struct command *);
 extern void doglob (Char **, struct command *);
 extern void dogoto (Char **, struct command *);
 extern void doif (Char **, struct command *);

sh.err.c

@@ -188,7 +188,8 @@ extern int enterhist;
 #define ERR_BADCOLORVAR 134
 #define ERR_EOF 135
 #define ERR_UNAVAILABLE 136
-#define NO_ERRORS 137
+#define ERR_DOLFUNC 137
+#define NO_ERRORS 138
 
 static const char *elst[NO_ERRORS] INIT_ZERO_STRUCT;
 
@@ -367,7 +368,7 @@ errinit(void)
  elst[ERR_BADCOLORVAR] = CSAVS(1, 137, "Unknown %s color variable '%c%c'");
  elst[ERR_EOF] = CSAVS(1, 138, "Unexpected end of file");
  elst[ERR_UNAVAILABLE] = CSAVS(1, 139, "%s: Feature is not available for this platform");
-
+ elst[ERR_DOLFUNC] = CSAVS(1, 140, "Functions are only supported for scripts");
 }
 
 /* Cleanup data. */
@@ -657,3 +658,16 @@ stderror(unsigned int id, ...)
 
  reset(); /* Unwind */
 }
+
+void
+funcerror(Char *n, Char *msg)
+{
+ char nconv[Strlen(n) + 1],
+ msgconv[Strlen(msg) + 1];
+
+ strcpy(nconv, short2str(n));
+ strcpy(msgconv, short2str(msg));
+
+ setname(nconv);
+ stderror(ERR_NAME | ERR_NOTFOUND, msgconv);
+}

sh.func.c

@@ -56,7 +56,6 @@ static void preread (void);
 static void doagain (void);
 static const char *isrchx (int);
 static void search (int, int, Char *);
-static int getword (struct Strbuf *);
 static struct wordent *histgetword (struct wordent *);
 static void toend (void);
 static void xecho (int, Char **);
@@ -742,8 +741,8 @@ isrchx(int n)
 }
 
 
-static int Stype;
-static Char *Sgoal;
+int Stype;
+Char *Sgoal;
 
 static void
 search(int type, int level, Char *goal)
@@ -1000,7 +999,7 @@ histgetword(struct wordent *histent)
  return NULL;
 }
 
-static int
+int
 getword(struct Strbuf *wp)
 {
  int found = 0, first;
@@ -1096,6 +1095,11 @@ getword(struct Strbuf *wp)
  stderror(ERR_NAME | ERR_NOTFOUND, "label");
  break;
 
+ case TC_EXIT:
+ setname(short2str(Sgoal));
+ stderror(ERR_NAME | ERR_NOTFOUND, "exit");
+ break;
+
  default:
  break;
  }
@@ -2719,3 +2723,41 @@ getYN(const char *prompt)
  continue;
  return doit;
 }
+
+void
+dofunction(Char **v, struct command *t)
+{
+ if (!ffile)
+ stderror(ERR_DOLFUNC);
+
+ {
+ int i, j;
+ Char **vh;
+
+ for (i = 0; v[i]; i++)
+ ;
+
+ vh = xmalloc((i + 2) * sizeof(Char *));
+ vh[i + 1] = NULL;
+
+ for (j = i--; i; i--, j--) {
+ vh[j] = xmalloc(((Strlen(v[i]) + 1) * sizeof(Char)));
+ Strcpy(vh[j], v[i]);
+ }
+ vh[1] = xmalloc(Strlen(ffile) + 1);
+ Strcpy(vh[1], ffile);
+ *vh = xmalloc(Strlen(*v) + 1);
+ Strcpy(*vh, *v);
+
+ if (fargv) {
+ fargv->next = malloc(sizeof *fargv);
+ fargv->next->prev = fargv;
+ fargv = fargv->next;
+ } else {
+ fargv = malloc(sizeof *fargv);
+ fargv->prev = NULL;
+ }
+
+ dosource(fargv->v = vh, fargv->t = t);
+ }
+}

sh.h

@@ -1305,5 +1305,15 @@ extern int filec;
 #define TEXP_IGNORE 1 /* in ignore, it means to ignore value, just parse */
 #define TEXP_NOGLOB 2 /* in ignore, it means not to globone */
 
+/* Function variable(s) and function(s). */
+extern Char *Sgoal;
+extern int Stype;
+extern struct funcargs {
+ Char **v;
+ struct command *t;
+ struct funcargs *prev,
+ *next;
+} *fargv;
+extern int getword(struct Strbuf *);
 
 #endif /* _h_sh */

sh.init.c

@@ -80,6 +80,7 @@ const struct biltins bfunc[] = {
  { "fg", dofg, 0, INF },
  { "filetest", dofiletest, 2, INF },
  { "foreach", doforeach, 3, INF },
+ { "function", dofunction, 1, INF },
 #ifdef TCF
  { "getspath", dogetspath, 0, 0 },
  { "getxvers", dogetxvers, 0, 0 },