Use snapshots of the stack to restore stack to its previous state

[fur] / templates / program.c

diff --git a/templates/program.c b/templates/program.c
index db1abdf..25f9acb 100644 (file)
--- a/templates/program.c
+++ b/templates/program.c
@@ -1,5 +1,6 @@
 #include <assert.h>
 #include <inttypes.h>
+#include <setjmp.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
@@ -66,7 +67,7 @@ typedef struct Closure Closure;
 struct Closure
 {
   Environment* closed;
-  Object (*call)(EnvironmentPool*, Environment*, size_t, Stack*);
+  Object (*call)(EnvironmentPool*, Environment*, size_t, Stack*, jmp_buf);
 };
 
 struct List;
@@ -162,6 +163,23 @@ void Stack_initialize(Stack* self)
   self->length = 0;
 }
 
+Stack* Stack_construct()
+{
+  Stack* result = malloc(sizeof(Stack));
+  Stack_initialize(result);
+  return result;
+}
+
+void Stack_destruct(Stack* self)
+{
+  free(self);
+}
+
+bool Stack_any(Stack* self)
+{
+  return self->length > 0;
+}
+
 void Stack_push(Stack* self, Object item)
 {
   assert(self->length < 256);
@@ -315,6 +333,22 @@ void Object_deinitialize(Object* self)
   }
 }
 
+typedef uint32_t StackSnapshot;
+
+StackSnapshot Stack_takeSnapshot(Stack* self)
+{
+  return (StackSnapshot) self->length;
+}
+
+void Stack_rewind(Stack* self, StackSnapshot snapshot)
+{
+  while(self->length > snapshot)
+  {
+    Object item = Stack_pop(self);
+    Object_deinitialize(&item);
+  }
+}
+
 void Environment_deinitialize(Environment* self)
 {
   EnvironmentNode* next;
@@ -516,6 +550,13 @@ Environment* EnvironmentPool_allocate(EnvironmentPool* self)
   return EnvironmentPool_allocate(previous->overflow);
 }
 
+Environment* Environment_construct(EnvironmentPool* environmentPool, Environment* parent)
+{
+  Environment* environment = EnvironmentPool_allocate(environmentPool);
+  Environment_initialize(environment, parent);
+  return environment;
+}
+
 Object integerLiteral(int32_t literal)
 {
   Object result;
@@ -544,7 +585,7 @@ Object operator$negate(Object input)
 }
 
 // TODO Make this conditionally added
-Object operator$concatenate(Stack* stack)
+Object operator$concatenate(Stack* stack, jmp_buf parentJump, size_t line)
 {
   Object right = Stack_pop(stack);
   Object left = Stack_pop(stack);
@@ -577,7 +618,7 @@ Object operator$concatenate(Stack* stack)
 }
 
 {% for id in infix_declarations %}
-Object operator${{ id.name }}(Stack* stack)
+Object operator${{ id.name }}(Stack* stack, jmp_buf parentJump, size_t line)
 {
   Object right = Stack_pop(stack);
   Object left = Stack_pop(stack);
@@ -585,6 +626,14 @@ Object operator${{ id.name }}(Stack* stack)
   assert(left.type == {{ id.in_type.upper() }});
   assert(right.type == {{ id.in_type.upper() }});
 
+  {% if id.name == 'integerDivide' or id.name == 'modularDivide' %}
+  if(right.instance.integer == 0)
+  {
+    fprintf(stderr, "DivisionByZeroError on line %zu\n", line);
+    longjmp(parentJump, 1);
+  }
+  {% endif %}
+
   Object result;
   result.type = {{ id.out_type.upper() }};
   result.instance.{{ id.out_type.lower() }} = left.instance.{{ id.in_type.lower() }} {{ id.operator }} right.instance.{{ id.in_type.lower() }};
@@ -593,7 +642,7 @@ Object operator${{ id.name }}(Stack* stack)
 {% endfor %}
 
 {% if 'pow' in builtins %}
-Object builtin$pow$implementation(EnvironmentPool* environmentPool, Environment* parent, size_t argc, Stack* stack)
+Object builtin$pow$implementation(EnvironmentPool* environmentPool, Environment* parent, size_t argc, Stack* stack, jmp_buf parentJump)
 {
   // Must unload items in reverse order
   Object exponent = Stack_pop(stack);
@@ -612,7 +661,7 @@ Object builtin$pow = { CLOSURE, (Instance)(Closure){ NULL, builtin$pow$implement
 {% endif %}
 
 {% if 'print' in builtins %}
-Object builtin$print$implementation(EnvironmentPool* environmentPool, Environment* parent, size_t argc, Stack* stack)
+Object builtin$print$implementation(EnvironmentPool* environmentPool, Environment* parent, size_t argc, Stack* stack, jmp_buf parentJump)
 {
   Stack reverse_stack;
   Stack_initialize(&reverse_stack);
@@ -642,9 +691,9 @@ Object builtin$print$implementation(EnvironmentPool* environmentPool, Environmen
 
       case STRING_CONCATENATION:
         Stack_push(stack, output.instance.string_concatenation->left);
-        builtin$print$implementation(NULL, NULL, 1, stack);
+        builtin$print$implementation(NULL, NULL, 1, stack, parentJump);
         Stack_push(stack, output.instance.string_concatenation->right);
-        builtin$print$implementation(NULL, NULL, 1, stack);
+        builtin$print$implementation(NULL, NULL, 1, stack, parentJump);
         break;
 
       case STRING_LITERAL:
@@ -682,6 +731,23 @@ int main(int argc, char** argv)
   Stack* stack = &stackMemory;
   Stack_initialize(stack);
 
+  jmp_buf jump;
+  if(setjmp(jump) != 0)
+  {
+    fprintf(stderr, "\tin __main__\n");
+
+    while(Stack_any(stack))
+    {
+      Object item = Stack_pop(stack);
+      Object_deinitialize(&item);
+    }
+    Environment_setLive(environment, false);
+    EnvironmentPool_destruct(environmentPool);
+
+    // TODO We would like to return something nonzero here, but that messes up Valgrind so we couldn't catch memory leaks
+    return 0;
+  }
+
   // TODO Use the symbol from SYMBOL_LIST
   {% for builtin in builtins %}
   Environment_set(environment, "{{ builtin }}", builtin${{ builtin }});