From 73effcd52ab51114ace9800c0465cc957fa1dc52 Mon Sep 17 00:00:00 2001
From: kamkow1 <kamkow256@gmail.com>
Date: Wed, 1 Oct 2025 21:26:22 +0200
Subject: [PATCH] tb Implement a string stack

---
 ulib/linklist.h   | 12 ++++++++++
 user/tb/interp.c  | 33 +++++++++++++++++++-------
 user/tb/runtime.c | 60 +++++++++++++++++++++++++++++++++++++++++++----
 user/tb/runtime.h |  9 +++++++
 4 files changed, 101 insertions(+), 13 deletions(-)

diff --git a/ulib/linklist.h b/ulib/linklist.h
index 07df5e7..0180315 100644
--- a/ulib/linklist.h
+++ b/ulib/linklist.h
@@ -68,4 +68,16 @@
        var != NULL && (idx) < (max); \
        var = tmp, tmp = (var ? var->next : NULL), (idx)++)
 
+#define LL_BACK(head, out) \
+  do { \
+    (out) = NULL; \
+    if ((head) != NULL) { \
+      typeof((head)) __tmp = (head); \
+      while (__tmp->next != NULL) { \
+        __tmp = __tmp->next; \
+      } \
+      (out) = __tmp; \
+    } \
+  } while(0)
+
 #endif // ULIB_LINKLIST_H_
diff --git a/user/tb/interp.c b/user/tb/interp.c
index 01cbdbc..0cf85ca 100644
--- a/user/tb/interp.c
+++ b/user/tb/interp.c
@@ -122,15 +122,30 @@ void tz_expandspecial(Tokenizer *tz) {
   Token *tk, *tktmp;
   LL_FOREACH_SAFE(tz->tokens, tk, tktmp) {
     if (tk->str[0] == '$' && string_len(tk->str) > 1) {
-      RtAlias *alias, *aliastmp;
-      LL_FOREACH_SAFE(RTALIASES, alias, aliastmp) {
-        if (string_strcmp(alias->namebuf, tk->str+1) == 0) {
-          ufree(tk->str);
-          size_t len = string_len(alias->valbuf)+1;
-          tk->str = umalloc(len);
-          string_memset(tk->str, 0, len);
-          string_memcpy(tk->str, alias->valbuf, string_len(alias->valbuf));
-          break;
+      if (string_strcmp(tk->str, "$stack") == 0) {
+        char *s = rtstringv_stackpeek();
+        ufree(tk->str);
+        if (s == NULL) {
+          tk->str = umalloc(1);
+          tk->str[0] = '\0';
+        } else {
+          size_t len = string_len(s);
+          char *copy = umalloc(len+1);
+          string_memcpy(copy, s, len);
+          copy[len] = '\0';
+          tk->str = copy;
+        }
+      } else {
+        RtAlias *alias, *aliastmp;
+        LL_FOREACH_SAFE(RTALIASES, alias, aliastmp) {
+          if (string_strcmp(alias->namebuf, tk->str+1) == 0) {
+            ufree(tk->str);
+            size_t len = string_len(alias->valbuf)+1;
+            tk->str = umalloc(len);
+            string_memset(tk->str, 0, len);
+            string_memcpy(tk->str, alias->valbuf, string_len(alias->valbuf));
+            break;
+          }
         }
       }
     }
diff --git a/user/tb/runtime.c b/user/tb/runtime.c
index 71dcf3a..eab552a 100644
--- a/user/tb/runtime.c
+++ b/user/tb/runtime.c
@@ -4,6 +4,38 @@
 #include "runtime.h"
 #include "interp.h"
 
+RtStringV *RTSTRINGV_STACK = NULL;
+
+void rtstringv_stackpushcopy(char *s, size_t len) {
+  char *c = umalloc(len+1);
+  string_memcpy(c, s, len);
+  c[len] = '\0';
+  RtStringV *v = umalloc(sizeof(*v));
+  v->data = c;
+  LL_APPEND(RTSTRINGV_STACK, v);
+}
+
+char *rtstringv_stackpop(void) {
+  RtStringV *v;
+  LL_BACK(RTSTRINGV_STACK, v);
+  if (v == NULL) {
+    return NULL;
+  }
+  LL_REMOVE(RTSTRINGV_STACK, v);
+  char *d = v->data;
+  ufree(v);
+  return d;
+}
+
+char *rtstringv_stackpeek(void) {
+  RtStringV *v;
+  LL_BACK(RTSTRINGV_STACK, v);
+  if (v == NULL) {
+    return NULL;
+  }
+  return v->data;
+}
+
 extern PID_t PID;
 
 RtCmd *RTCMDS = NULL;
@@ -25,7 +57,6 @@ bool rt_print(Token *tks) {
       uprintf(" ");
     }
   }
-  uprintf("\n");
   return true;
 }
 
@@ -52,7 +83,7 @@ bool rt_PID(Token *tks) {
   return true;
 }
 
-bool rt_subsh(Token *tks) {
+bool rt_do(Token *tks) {
   bool ok = true;
 
   char *prepended_args[] = { "-m", "runstring", "-preload", "base:/scripts/rc.tb", "-rs" };
@@ -100,11 +131,15 @@ bool rt_subsh(Token *tks) {
     string_memset(buf, 0, sizeof(buf));
     
     r = ipcpipe(app, IPCPIPE_OUT, IPCPIPE_READ, (uint8_t *)buf, sizeof(buf)-1);
-    stringbuffer_appendcstr(&outbuf, buf);
+    if (r > 0) {
+      stringbuffer_appendcstr(&outbuf, buf);
+    }
   }
 
   ipcpipe(PID, 10, IPCPIPE_DELETE, NULL, 0);
 
+  rtstringv_stackpushcopy(outbuf.data, outbuf.count);
+
   stringbuffer_free(&outbuf);
 
 done:
@@ -116,9 +151,26 @@ done:
   return ok;
 }
 
+bool rt_stackpush(Token *tks) {
+  Token *tk, *tktmp;
+  LL_FOREACH_SAFE(tks, tk, tktmp) {
+    rtstringv_stackpushcopy(tk->str, string_len(tk->str));
+  }
+  return true;
+}
+
+bool rt_stackpop(Token *tks) {
+  (void)tks;
+  char *s = rtstringv_stackpop();
+  if (s) ufree(s);
+  return true;
+}
+
 void rt_init(void) {
   RTCMD("%print", &rt_print);
   RTCMD("%mkalias", &rt_mkalias);
   RTCMD("%PID", &rt_PID);
-  RTCMD("%subsh", &rt_subsh);
+  RTCMD("%do", &rt_do);
+  RTCMD("%stackpush", &rt_stackpush);
+  RTCMD("%stackpop", &rt_stackpop);
 }
diff --git a/user/tb/runtime.h b/user/tb/runtime.h
index 9287488..fb7140f 100644
--- a/user/tb/runtime.h
+++ b/user/tb/runtime.h
@@ -20,9 +20,18 @@ typedef struct RtAlias {
   char valbuf[RTALIAS_VALBUF_MAX];
 } RtAlias;
 
+typedef struct RtStringV {
+  struct RtStringV *next;
+  char *data;
+} RtStringV;
+
 void rt_init(void);
 
 extern RtCmd *RTCMDS;
 extern RtAlias *RTALIASES;
 
+void rtstringv_stackpushcopy(char *s, size_t len);
+char *rtstringv_stackpop(void);
+char *rtstringv_stackpeek(void);
+
 #endif // TB_RUNTIME_H_