From faaf40e55e002212c0c28f7845dfa2322eb7ad05 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Thu, 21 Oct 2021 11:43:13 -0700
Subject: feat(rc): string concatenation works

---
 sys/cmd/rc/exec.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 46 insertions(+), 3 deletions(-)

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

diff --git a/sys/cmd/rc/exec.c b/sys/cmd/rc/exec.c
index 6d0c0a9..ac0dc08 100644
--- a/sys/cmd/rc/exec.c
+++ b/sys/cmd/rc/exec.c
@@ -578,6 +578,52 @@ Xword(void)
     pushword(runner->code.exe[runner->code.i++].s);
 }
 
+static
+Word*
+catlist(Word *l, Word *r, Word *tail)
+{
+    Word *w;
+    char *buf;
+
+    if(l->link || r->link)
+        tail = catlist( (!l->link)?l:l->link, (!r->link)?r:r->link, tail);
+
+    buf = emalloc(strlen(l->str)+strlen(r->str)+1);
+    strcpy(buf, l->str);
+    strcat(buf, r->str);
+
+    w = makeword(buf, tail);
+    efree(buf);
+
+    return w;
+}
+
+void
+Xconcatenate(void)
+{
+    int rn, ln;
+    Word *l = runner->args->word;
+    Word *r = runner->args->link->word;
+    Word *w = runner->args->link->link->word;
+
+    ln = count(l), rn = count(r);
+    if(ln != 0 || rn != 0) {
+        if(ln == 0 || rn == 0){
+            Xerror("null list in concatenation\n");
+            return;
+        }
+        if(ln != 1 && rn != 1 && ln != rn) {
+            Xerror("mismatched list lengths in concatenation\n");
+            return;
+        }
+        w = catlist(l, r, w);
+    }
+
+    poplist();
+    poplist();
+    runner->args->word = w;
+}
+
 void
 Xdollar(void)
 {
@@ -638,7 +684,6 @@ Xassign(void)
     poplist();
 }
 
-
 void
 Xreadcmd(void)
 {
@@ -982,8 +1027,6 @@ Xreturn(void)
         exit(0);
 }
 
-
-
 void
 Xexit(void)
 {
-- 
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