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[fork] interactive rc shell
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commit 2325713c2f574aa08b5ad1bb91a3e4ee30b6b0b5
parent 7dc3033c862c30d8998ed3e4c98c056286f31401
Author: Drazen Borkovic <borkovic@users.noreply.github.com>
Date:   Sat, 26 Aug 2017 16:19:50 -0700

Add "continue" builtin

Diffstat:

Mbuiltins.c | 19+++++++++++++++----


Mexcept.c | 9++++++---


Minput.c | 4++--


Mrc.h | 4++--


Mtrip.rc | 72++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


Mwalk.c | 83++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------


6 files changed, 154 insertions(+), 37 deletions(-)

diff --git a/builtins.c b/builtins.c
@@ -20,7 +20,7 @@
 #include "rlimit.h"
 #include "sigmsgs.h"
 
-static void b_break(char **), b_cd(char **), b_eval(char **), b_exit(char **),
+static void b_break(char **), b_cd(char **), b_continue(char **), b_eval(char **), b_exit(char **),
 	b_newpgrp(char **), b_return(char **), b_shift(char **), b_umask(char **),
 	b_wait(char **), b_whatis(char **);
 
@@ -39,6 +39,7 @@ static struct {
 	{ b_break,	"break" },
 	{ b_builtin,	"builtin" },
 	{ b_cd,		"cd" },
+	{ b_continue,   "continue" },
 #if RC_ECHO
 	{ b_echo,	"echo" },
 #endif
@@ -83,8 +84,8 @@ extern void funcall(char **av) {
 	except(eVarstack, star, &e2);
 	walk(treecpy(fnlookup(*av), nalloc), TRUE);
 	varrm("*", TRUE);
-	unexcept(); /* eVarstack */
-	unexcept(); /* eReturn */
+	unexcept(eVarstack); 
+	unexcept(eReturn); 
 }
 
 static void arg_count(char *name) {
@@ -216,6 +217,16 @@ static void b_break(char **av) {
 	rc_raise(eBreak);
 }
 
+/* raise a "continue" exception to finish early an iteration of 'for' and 'while' loops */
+
+static void b_continue(char **av) {
+	if (av[1] != NULL) {
+		arg_count("continue");
+		return;
+	}
+	rc_raise(eContinue);
+}
+
 /* shift $* n places (default 1) */
 
 static void b_shift(char **av) {
@@ -401,7 +412,7 @@ extern void b_dot(char **av) {
 	except(eVarstack, star, &e);
 	doit(TRUE);
 	varrm("*", TRUE);
-	unexcept(); /* eVarstack */
+	unexcept(eVarstack);
 	interactive = old_i;
 }
 
diff --git a/except.c b/except.c
@@ -22,13 +22,14 @@ extern void except(ecodes e, Edata data, Estack *ex) {
 	estack = ex;
 	estack->e = e;
 	estack->data = data;
-	if (e == eError || e == eBreak || e == eReturn)
+	if (e == eError || e == eBreak || e == eReturn || e == eContinue)
 		estack->interactive = interactive;
 }
 
 /* remove an exception, restore last interactive value */
 
-extern void unexcept() {
+extern void unexcept(ecodes e) {
+	assert(e == estack->e);
 	switch (estack->e) {
 	default:
 		break;
@@ -66,8 +67,10 @@ extern void rc_raise(ecodes e) {
 		exit(1); /* child processes exit on an error/signal */
 	for (; estack != NULL; estack = estack->prev)
 		if (estack->e != e) {
-			if (e == eBreak && estack->e != eArena && estack->e != eVarstack)
+			if (e == eBreak && (estack->e != eArena && estack->e != eVarstack && estack->e != eContinue))
 				rc_error("break outside of loop");
+			else if (e == eContinue && (estack->e != eVarstack))
+				rc_error("continue outside of loop");
 			else if (e == eReturn && estack->e == eError) /* can return from loops inside functions */
 				rc_error("return outside of function");
 			switch (estack->e) {
diff --git a/input.c b/input.c
@@ -314,10 +314,10 @@ extern Node *doit(bool clobberexecit) {
 			else if (dashex && dashen)
 				fprint(2, "%T\n", parsetree);
 		}
-		unexcept(); /* eArena */
+		unexcept(eArena);
 	}
 	popinput();
-	unexcept(); /* eError */
+	unexcept(eError);
 	return parsetree;
 }
 
diff --git a/rc.h b/rc.h
@@ -41,7 +41,7 @@ typedef enum nodetype {
 } nodetype;
 
 typedef enum ecodes {
-	eError, eBreak, eReturn, eVarstack, eArena, eFifo, eFd
+	eError, eBreak, eReturn, eVarstack, eArena, eFifo, eFd, eContinue
 } ecodes;
 
 typedef enum bool {
@@ -185,7 +185,7 @@ extern bool outstanding_cmdarg(void);
 extern void pop_cmdarg(bool);
 extern void rc_raise(ecodes);
 extern void except(ecodes, Edata, Estack *);
-extern void unexcept(void);
+extern void unexcept(ecodes e);
 extern void rc_error(char *);
 extern void sigint(int);
 
diff --git a/trip.rc b/trip.rc
@@ -598,6 +598,78 @@ x=$tmpdir/qux*/foo
 
 rm -rf $tmpdir
 
+#############################################################################
+## Check builtin continue in while loop.
+#############################################################################
+q=''''
+C=$q^while-continue$q
+L=()
+
+ten = a^(1 2 3 4 5 6 7 8 9 10)
+* = $ten
+for (n) {
+  if (~ $n a2 a3) {
+    continue
+  }
+  L=($L $n)
+}
+if (!~ $#L 8) {
+  fail Wrong length of list from $C: $#L
+}
+if (!~ $L(1) a1) {
+  fail First element of $C list is not a1: $L(1)
+}
+if (!~ $L(2) a4) {
+  fail Second element of $C list is not a4: $L(2)
+}
+C=() L=()
+
+#############################################################################
+## Check builtin continue in for loop.
+#############################################################################
+C=$q^for-continue$q
+L=()
+
+for (x in a b c d e f g) {
+  if (~ $x c f) {
+    continue
+  }
+  L=($L $x)
+}
+if (!~ $#L 5) {
+  fail Wrong length of list from $C
+}
+if (!~ $L(1) a) {
+  fail First element of $C list is not a: $L(1)
+}
+if (!~ $L(3) d) {
+  fail Third element of $C list is not d: $L(3)
+}
+if (!~ $L(5) g) {
+  fail Fifth element of $C list is not g: $L(5)
+}
+C=() L=()
+
+submatch continue 'rc: continue outside of loop' 'continue outside of loop'
+
+#############################################################################
+## check builtin continue in for loop (2)
+#############################################################################
+L=()
+for (x in a b c d e f g) {
+  if (~ $x b d) {
+    continue
+  }
+  L=($L $x)
+  if (~ $x f) {
+    break;
+  }
+}
+
+if (!~ $^L 'a c e f') {
+  fail List should be '(a c e f)', but is $L
+}
+
 # test support for unquoted =
 submatch 'echo foo = bar' 'foo = bar' 'unquoted equals 2'
 submatch 'echo foo=bar' 'foo=bar' 'unquoted equals 2'
diff --git a/walk.c b/walk.c
@@ -17,6 +17,7 @@ static bool haspreredir(Node *);
 static bool isallpre(Node *);
 static bool dofork(bool);
 static void dopipe(Node *);
+static void loop_body(Node* n);
 
 /* Tail-recursive version of walk() */
 
@@ -101,52 +102,58 @@ top:	sigchk();
 		WALK(true_cmd, parent);
 	}
 	case nWhile: {
-		Jbwrap j;
-		Edata jbreak;
-		Estack e1, e2;
-		bool testtrue, oldcond = cond;
+		Jbwrap break_jb;
+		Edata  break_data;
+		Estack break_stack;
+		bool testtrue;
+		const bool oldcond = cond;
 		cond = TRUE;
 		if (!walk(n->u[0].p, TRUE)) { /* prevent spurious breaks inside test */
 			cond = oldcond;
 			break;
 		}
 		cond = oldcond;
-		if (sigsetjmp(j.j, 1))
+		if (sigsetjmp(break_jb.j, 1))
 			break;
-		jbreak.jb = &j;
-		except(eBreak, jbreak, &e1);
+		break_data.jb = &break_jb;
+		except(eBreak, break_data, &break_stack);
+
+		cond = oldcond;
 		do {
-			Edata block;
-			block.b = newblock();
-			except(eArena, block, &e2);
-			walk(n->u[1].p, TRUE);
+			Edata  iter_data;
+			Estack iter_stack;
+			iter_data.b = newblock();
+			except(eArena, iter_data, &iter_stack);
+			loop_body(n->u[1].p);
 			cond = TRUE;
 			testtrue = walk(n->u[0].p, TRUE);
 			cond = oldcond;
-			unexcept(); /* eArena */
+			unexcept(eArena);
 		} while (testtrue);
 		cond = oldcond;
-		unexcept(); /* eBreak */
+		unexcept(eBreak);
 		break;
 	}
 	case nForin: {
 		List *l, *var = glom(n->u[0].p);
-		Jbwrap j;
-		Estack e1, e2;
-		Edata jbreak;
-		if (sigsetjmp(j.j, 1))
+		Jbwrap break_jb;
+		Edata  break_data;
+		Estack break_stack;
+		if (sigsetjmp(break_jb.j, 1))
 			break;
-		jbreak.jb = &j;
-		except(eBreak, jbreak, &e1);
+		break_data.jb = &break_jb;
+		except(eBreak, break_data, &break_stack);
+
 		for (l = listcpy(glob(glom(n->u[1].p)), nalloc); l != NULL; l = l->n) {
-			Edata block;
+			Edata  iter_data;
+			Estack iter_stack;
 			assign(var, word(l->w, NULL), FALSE);
-			block.b = newblock();
-			except(eArena, block, &e2);
-			walk(n->u[2].p, TRUE);
-			unexcept(); /* eArena */
+			iter_data.b = newblock();
+			except(eArena, iter_data, &iter_stack);
+			loop_body(n->u[2].p);
+			unexcept(eArena);
 		}
-		unexcept(); /* eBreak */
+		unexcept(eBreak);
 		break;
 	}
 	case nSubshell:
@@ -240,7 +247,7 @@ top:	sigchk();
 				except(eVarstack, var, &e);
 				walk(n->u[1].p, parent);
 				varrm(v->w, TRUE);
-				unexcept(); /* eVarstack */
+				unexcept(eVarstack);
 			}
 		} else
 			panic("unexpected node in preredir section of walk");
@@ -364,3 +371,27 @@ static void dopipe(Node *n) {
 	setpipestatus(stats, i);
 	sigchk();
 }
+
+/* From http://en.cppreference.com/w/c/program/setjmp
+ * According to the C standard setjmp() must appear only in the following 4 constructs:
+ *   1. switch (setjmp(args)) {statements}
+ *   2. if (setjmp(args) == Const) {statements} with any of 
+ *             operators: ==, !=, <, >, <=, >=
+ *   3. while (! setjmp(args)) {statements}
+ *   4. setjmp(args);
+*/
+static void loop_body(Node* nd)
+{
+	Node *volatile n = nd;
+	Jbwrap cont_jb;
+	Edata  cont_data;
+	Estack cont_stack;
+
+	if (sigsetjmp(cont_jb.j, 1) == 0) {
+		cont_data.jb = &cont_jb;
+		except(eContinue, cont_data, &cont_stack);
+		walk(n, TRUE);
+		unexcept(eContinue);
+	}
+}
+