From e9ff1c6fbbbac9ece2604876ab589ac282360446 Mon Sep 17 00:00:00 2001
From: Nicholas <nbnoll@eml.cc>
Date: Mon, 15 Nov 2021 15:08:03 -0800
Subject: Feat: added if/else branching and switch statement

Unsure about my modification to the language. I found the parsing of the
case body within switches to be odd - specifically that it parses
liberally and then checks that it has case -> cmd structuring while it
walks the code. This means the language is more permissive than the
semantics. I modified it to be more explicit, but at the cost of having
to end each case statement with a semicolon. I wanted a colon, but this
is a valid word character and thus will be lexed as part of the word.
---
 src/cmd/rc/exec.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 59 insertions(+), 4 deletions(-)

(limited to 'src/cmd/rc/exec.c')

diff --git a/src/cmd/rc/exec.c b/src/cmd/rc/exec.c
index 5baaf1a..a551d52 100644
--- a/src/cmd/rc/exec.c
+++ b/src/cmd/rc/exec.c
@@ -360,6 +360,18 @@ count(Word *w)
 // -----------------------------------------------------------------------
 // builtins
 
+static void
+setstatus(char *msg)
+{
+    if(!msg || msg[0] == 0)
+        runner->status = 0;
+    else
+        runner->status = 1;
+}
+
+// -----------------------------------------------------------------------
+// builtins
+
 void
 xecho(void)
 {
@@ -402,10 +414,13 @@ xexit(void)
     Word *arg;
 
     popword(); // exit
+
     arg = runner->args->word;
     switch(count(arg)){
     default:
         print(shell.err, "invalid number of arguments to exit, exiting anyways\n");
+    case 1:
+        setstatus(runner->args->word->str);
     case 0:
         Xexit();
     }
@@ -420,19 +435,24 @@ xcd(void)
     char dir[512];
 
     popword(); // cd
+    setstatus(nil);
 
     arg = runner->args->word;
     switch(count(arg)){
     default:
         print(shell.err, "usage: cd [directory]\n");
+        setstatus("failed cd");
         break;
     case 0:
         arg = var("home")->val;
         if(count(arg) >= 1){
-            if(chdir(arg->str) < 0)
+            if(chdir(arg->str) < 0){
                 print(shell.err, "failed cd: %s\n", strerror(errno));
+                setstatus("failed cd");
+            }
         }else{
             print(shell.err, "ambiguous cd: $home empty\n");
+            setstatus("failed cd");
         }
         break;
 
@@ -443,9 +463,12 @@ xcd(void)
             strcpy(dir, cdpath->str);
             if(dir[0])
                 strcat(dir,"/");
+
             strcat(dir, arg->str);
+
             if(chdir(dir) < 0){
                 print(shell.err, "failed cd %s: %s\n", dir, strerror(errno));
+                setstatus("failed cd");
             }
             break;
         }
@@ -510,6 +533,8 @@ xdot(void)
 
     if(fd<0){
         print(shell.err, "failed open: %s: ", base);
+        setstatus("failed open");
+        Xerror(".: failed open");
         return;
     }
     /* set up for a new command loop */
@@ -632,13 +657,21 @@ Xword(void)
     pushword(runner->code.exe[runner->code.i++].s);
 }
 
+void
+Xsettrue(void)
+{
+    setstatus(nil);
+}
+
 void
 Xtrue(void)
 {
     if(!runner->status){
-        assert(runner->wait.status == Pdone);
         runner->code.i++;
-        deljob(runner);
+        if(runner->wait.status){
+            assert(runner->wait.status == Pdone);
+            deljob(runner);
+        }
         runner->pgid = -1;
     }else
         runner->code.i = runner->code.exe[runner->code.i].i;
@@ -662,6 +695,27 @@ Xgoto(void)
     runner->code.i = runner->code.exe[runner->code.i].i;
 }
 
+void
+Xcase(void)
+{
+    Word *p; // pattern
+    Word *c; // case value
+
+    for(p=runner->args->word; p; p=p->link){
+        for(c=runner->args->link->word; c; c=c->link){
+            if(match(c->str, p->str, 0))
+                goto hit;
+        }
+    }
+nohit:
+    runner->code.i = runner->code.exe[runner->code.i].i;
+    goto clean;
+hit:
+    runner->code.i++;
+clean:
+    poplist(); // pop case words
+}
+
 void
 Xfor(void)
 {
@@ -678,7 +732,6 @@ Xfor(void)
         runner->local->val->link = nil;
         runner->code.i++;
     }
-
 }
 
 static
@@ -1261,6 +1314,8 @@ Xerror(char *msg)
 {
     print(shell.err, "rc: %s", msg);
     flush(shell.err);
+
+    setstatus("error");
     while(!runner->flag.user)
         Xreturn();
 }
-- 
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