Squashed 'lispBM/lispBM/' changes from a5683c69..075fd296

075fd296 fix bug related to pattern matching guards
02b38d42 update lbmref
fb312618 update lbmref
884a0973 update lbmref
32af7455 update lbmref

git-subtree-dir: lispBM/lispBM
git-subtree-split: 075fd296a8c6061ae8c5a45b017392700675b1d8

doc/lbmref.md

@@ -12,6 +12,7 @@ used as a value in and of itself a value (or data). So it can be used
 to name data and functions and is itself also data.
 
 ---
+
 **NOTE**
 
 Symbols are expressed as strings in your program such as `a`, `let`,
@@ -1238,6 +1239,15 @@ For example the match expression below evaluates to 2.
 
 ---
 
+### no_match
+
+The `no_match` symbol is returned from pattern matching if
+no case matches the expression.
+
+    - Add a catch-all case to your pattern-matching. `_`.
+
+---
+
 ### _
 
 The underscore pattern matches anything.
@@ -1506,21 +1516,30 @@ Below is an example that conditionally returns.
 
 ---
 
-## Unparsable symbols
+## Error handling
 
-Unparsable symbols cannot be written into a program. The unparsable symbols
-signals different kinds of error conditions that may point at something
-being wrong in the code (or that it is exhausting all resources).
+If an error occurs while evaluating a program, the process that runs
+that program is killed.  The result of the killed process is set to an
+error symbol indicating what went wrong.
 
-### no_match
+If the process was created using `spawn` (or equivalently, started by a
+issuing a command in the repl), the process dies and an error message
+is presented over the registered printing callback (dependent on how LispBM
+is integrated into your system). The `ctx_done_callback` is also called
+and performs other integration dependent tasks related to the shutting down
+of a process.
 
-The `no_match` symbol is returned from pattern matching if
-no case matches the expression. 
-
-    - Add a catch-all case to your pattern-matching. `_`. 
+If the process was created using `spawn-trap`, in addition to the
+above, a message is sent to the parent process (the process that
+executed the spawn-trap) containing information about the process that
+struck an error. See <a href="#spawn-trap">spawn-trap</a>.
+The parent process can now choose to restart the process that crashed
+or to take some other action.
 
 ---
 
+## Error Symbols
+
 ### read_error
 
 The `read_error` symbol is returned if the reader cannot
@@ -1669,7 +1688,7 @@ A value with type `type-u` occupy 28bits on the 32 bit version of LBM and
 
 ---
 
-### type-stream
+### type-channel
 
 ---
 

include/lbm_version.h

@@ -34,6 +34,7 @@ extern "C" {
 /*! \page changelog Changelog
 
 Nov 9: Version 0.7.1
+  - Bugfix: string literal lengths.
   - not-eq and != added.
   - Corrected behaviour for eval when applied to no argument.
   - lbm_memory operations are protected by mutex.

src/eval_cps.c

@@ -2246,7 +2246,7 @@ static void cont_match(eval_context_t *ctx) {
     if (match(pattern, e, &new_env, &do_gc)) {
       if (check_guard) {
         CHECK_STACK(lbm_push_3(&ctx->K, lbm_cdr(patterns), ctx->curr_env, MATCH));
-        CHECK_STACK(lbm_push_3(&ctx->K, body, e, MATCH_GUARD));
+        CHECK_STACK(lbm_push_4(&ctx->K, new_env, body, e, MATCH_GUARD));
         ctx->curr_env = new_env;
         ctx->curr_exp = n1; // The guard
       } else {
@@ -2267,7 +2267,7 @@ static void cont_match(eval_context_t *ctx) {
       }
       if (check_guard) {
         CHECK_STACK(lbm_push_3(&ctx->K, lbm_cdr(patterns), ctx->curr_env, MATCH));
-        CHECK_STACK(lbm_push_3(&ctx->K, body, e, MATCH_GUARD));
+        CHECK_STACK(lbm_push_4(&ctx->K, new_env, body, e, MATCH_GUARD));
         ctx->curr_env = new_env;
         ctx->curr_exp = n1; // The guard
       } else {
@@ -2354,14 +2354,16 @@ static void cont_match_guard(eval_context_t *ctx) {
   if (lbm_is_symbol_nil(ctx->r)) {
     lbm_value e;
     lbm_pop(&ctx->K, &e);
-    lbm_stack_drop(&ctx->K, 1);
+    lbm_stack_drop(&ctx->K, 2);
     ctx->r = e;
     ctx->app_cont = true;
   } else {
     lbm_value body;
+    lbm_value env;
     lbm_stack_drop(&ctx->K, 1);
-    lbm_pop(&ctx->K, &body);
+    lbm_pop_2(&ctx->K, &body, &env);
     lbm_stack_drop(&ctx->K, 3);
+    ctx->curr_env = env;
     ctx->curr_exp = body;
   }
 }

tests/test_match_guard_6.lisp

@@ -0,0 +1,9 @@
+
+(defun f (x)
+  (match x
+         ( (? x) (< x 5) 'smaller)
+         ( (? x) (> x 5) 'larger) 
+         ( _ 'whatever)))
+
+(and (eq (f 23) 'larger)
+     (eq (f 0.3) 'smaller))

tests/test_match_guard_7.lisp

@@ -0,0 +1,9 @@
+
+(defun f (x)
+  (match x
+         ( (? x) (< x 5) (list x 'smaller))
+         ( (? x) (> x 5) (list x 'larger)) 
+         ( _ 'whatever)))
+
+(and (eq (f 23) '(23 larger))
+     (eq (f 0.3) '(0.3 smaller)))