Add a string concatenation operator

diff --git a/examples/27_string_concatenation.fur b/examples/27_string_concatenation.fur
new file mode 100644 (file)
index 0000000..56bad3c
--- /dev/null
+++ b/examples/27_string_concatenation.fur
@@ -0,0 +1 @@
+print('Hello' ++ ', ' ++ 'world' ++ '\n')

diff --git a/examples/27_string_concatenation.fur.output.txt b/examples/27_string_concatenation.fur.output.txt
new file mode 100644 (file)
index 0000000..a5c1966
--- /dev/null
+++ b/examples/27_string_concatenation.fur.output.txt
@@ -0,0 +1 @@
+Hello, world

diff --git a/generation.py b/generation.py
index b060376..bc2e2c1 100644 (file)
--- a/generation.py
+++ b/generation.py
@@ -12,7 +12,10 @@ def generate_integer_literal(c_integer_literal):
     return 'integerLiteral({})'.format(c_integer_literal.value)
 
 def generate_string_literal(c_string_literal):
-    return 'stringLiteral(STRING_LITERAL_LIST[{}])'.format(c_string_literal.index)
+    return 'stringLiteral(STRING_LITERAL_LIST[{}] /* string: {} */)'.format(
+        c_string_literal.index,
+        repr(c_string_literal.value),
+    )
 
 def generate_symbol_expression(symbol_expression):
     return 'Environment_get(environment, SYMBOL_LIST[{}] /* symbol: {} */)'.format(
@@ -72,8 +75,7 @@ def generate_function_call(function_call):
     )
 
 def generate_expression_statement(statement):
-    # TODO Do we need to garbage collect the results of arbitrary statements?
-    return '{};'.format(generate_expression(statement.expression))
+    return 'Object_deinitialize(&({}));'.format(generate_expression(statement.expression))
 
 def generate_symbol_assignment_statement(statement):
     return 'Environment_set(environment, SYMBOL_LIST[{}] /* symbol: {} */, {});'.format(

diff --git a/normalization.py b/normalization.py
index ca6f57f..fbe3d04 100644 (file)
--- a/normalization.py
+++ b/normalization.py
@@ -293,14 +293,23 @@ def normalize_function_call_expression(counter, expression):
         function_expression = NormalVariableExpression(variable=function_variable)
         counter += 1
 
+    result_variable = '${}'.format(counter)
+
+    prestatements.append(
+        NormalVariableInitializationStatement(
+            variable=result_variable,
+            expression=NormalFunctionCallExpression(
+                function_expression=function_expression,
+                argument_count=len(arguments),
+                argument_items=NormalVariableExpression(variable=arguments_variable),
+            ),
+        )
+    )
+
     return (
-        counter,
+        counter + 1,
         tuple(prestatements),
-        NormalFunctionCallExpression(
-            function_expression=function_expression,
-            argument_count=len(arguments),
-            argument_items=NormalVariableExpression(variable=arguments_variable),
-        ),
+        NormalVariableExpression(variable=result_variable),
     )
 
 def normalize_basic_infix_operation(counter, expression):

diff --git a/templates/program.c b/templates/program.c
index 1766967..25bb413 100644 (file)
--- a/templates/program.c
+++ b/templates/program.c
@@ -53,7 +53,8 @@ enum Type
   CLOSURE,
   INTEGER,
   LIST,
-  STRING,
+  STRING_CONCATENATION,
+  STRING_LITERAL,
   VOID
 };
 
@@ -74,13 +75,17 @@ struct List
   Object* items;
 };
 
+struct StringConcatenation;
+typedef struct StringConcatenation StringConcatenation;
+
 union Instance
 {
   bool boolean;
   Closure closure;
   int32_t integer;
   List list;
-  const char* string;
+  StringConcatenation* string_concatenation;
+  const char* string_literal;
 };
 
 struct Object
@@ -93,6 +98,13 @@ const Object builtin$true = { BOOLEAN, (Instance)(bool){ true } };
 const Object builtin$false = { BOOLEAN, (Instance)(bool){ false } };
 const Object builtin$nil = { VOID, { 0 } };
 
+struct StringConcatenation
+{
+  size_t referenceCount;
+  Object left;
+  Object right;
+};
+
 Object List_construct(size_t allocate)
 {
   Object* items = malloc(sizeof(Object) * allocate);
@@ -151,30 +163,52 @@ void Environment_initialize(Environment* self, Environment* parent)
   self->live = true;
 }
 
-void Environment_deinitialize(Environment* self)
+void Object_deinitialize(Object* self)
 {
-  EnvironmentNode* next;
-  for(EnvironmentNode* node = self->root; node != NULL; node = next)
+  switch(self->type)
   {
-    next = node->next;
+    case BOOLEAN:
+      break;
+    case CLOSURE:
+      break;
+    case INTEGER:
+      break;
+    case STRING_LITERAL:
+      break;
+    case VOID:
+      break;
+
+    case LIST:
+      for(size_t i = 0; i < self->instance.list.length; i++) {
+        Object_deinitialize(&(self->instance.list.items[i]));
+      }
 
-    switch(node->value.type)
-    {
-      case BOOLEAN:
-      case CLOSURE:
-      case INTEGER:
-      case STRING:
-      case VOID:
-        break;
+      free(self->instance.list.items);
+      break;
 
-      case LIST:
-        free(node->value.instance.list.items);
-        break;
+    case STRING_CONCATENATION:
+      self->instance.string_concatenation->referenceCount--;
 
-      default:
-        assert(false);
-    }
+      if(self->instance.string_concatenation->referenceCount == 0)
+      {
+        Object_deinitialize(&(self->instance.string_concatenation->left));
+        Object_deinitialize(&(self->instance.string_concatenation->right));
+        free(self->instance.string_concatenation);
+      }
+      break;
 
+    default:
+      assert(false);
+  }
+}
+
+void Environment_deinitialize(Environment* self)
+{
+  EnvironmentNode* next;
+  for(EnvironmentNode* node = self->root; node != NULL; node = next)
+  {
+    next = node->next;
+    Object_deinitialize(&(node->value));
     free(node);
   }
 }
@@ -199,7 +233,7 @@ void Environment_mark(Environment* self)
     {
       case BOOLEAN:
       case INTEGER:
-      case STRING:
+      case STRING_LITERAL:
       case VOID:
         break;
 
@@ -380,8 +414,8 @@ Object integerLiteral(int32_t literal)
 Object stringLiteral(const char* literal)
 {
   Object result;
-  result.type = STRING;
-  result.instance.string = literal;
+  result.type = STRING_LITERAL;
+  result.instance.string_literal = literal;
   return result;
 }
 
@@ -396,6 +430,42 @@ Object operator$negate(Object input)
   return result;
 }
 
+// TODO Make this conditionally added
+Object operator$concatenate(Object left, Object right)
+{
+  switch(left.type) {
+    case STRING_CONCATENATION:
+      left.instance.string_concatenation->referenceCount++;
+      break;
+
+    case STRING_LITERAL:
+      break;
+
+    default:
+      assert(false);
+  }
+
+  switch(right.type) {
+    case STRING_CONCATENATION:
+      right.instance.string_concatenation->referenceCount++;
+      break;
+
+    case STRING_LITERAL:
+      break;
+
+    default:
+      assert(false);
+  }
+
+  StringConcatenation* concatenation = malloc(sizeof(StringConcatenation));
+  concatenation->referenceCount = 1;
+  concatenation->left = left;
+  concatenation->right = right;
+
+  Object result = { STRING_CONCATENATION, (Instance)concatenation };
+  return result;
+}
+
 {% for id in infix_declarations %}
 Object operator${{ id.name }}(Object left, Object right)
 {
@@ -450,9 +520,14 @@ Object builtin$print$implementation(EnvironmentPool* environmentPool, Environmen
         printf("%" PRId32, output.instance.integer);
         break;
 
-      case STRING:
+      case STRING_CONCATENATION:
+        builtin$print$implementation(NULL, NULL, 1, &(output.instance.string_concatenation->left));
+        builtin$print$implementation(NULL, NULL, 1, &(output.instance.string_concatenation->right));
+        break;
+
+      case STRING_LITERAL:
         // Using fwrite instead of printf to handle size_t length
-        printf("%s", output.instance.string);
+        printf("%s", output.instance.string_literal);
         break;
 
       case VOID:
@@ -462,6 +537,7 @@ Object builtin$print$implementation(EnvironmentPool* environmentPool, Environmen
       default:
         assert(false);
     }
+    Object_deinitialize(&output);
   }
 
   // TODO Return something better

diff --git a/tokenization.py b/tokenization.py
index e12b8ec..33f4331 100644 (file)
--- a/tokenization.py
+++ b/tokenization.py
@@ -43,7 +43,7 @@ _TOKEN_MATCHERS = [
     ('single_quoted_string_literal',    r"'.*?'"),
     ('comparison_level_operator',       r'(<=|>=|==|!=|<|>)'),
     ('assignment_operator',             r'='),
-    ('addition_level_operator',         r'(\+|-)'),
+    ('addition_level_operator',         r'(\+\+|\+|-)'),
     ('multiplication_level_operator',   r'(\*|//|%)'),
     ('newline',                         r'\n'),
 ]

diff --git a/transformation.py b/transformation.py
index 51b0244..e06bcf0 100644 (file)
--- a/transformation.py
+++ b/transformation.py
@@ -140,6 +140,7 @@ CProgram = collections.namedtuple(
 )
 
 BUILTINS = {
+    'concatenate':      [],
     'false':            [],
     'pow':              ['math.h'],
     'print':            ['stdio.h'],
@@ -185,7 +186,11 @@ CInfixDeclaration = collections.namedtuple(
     ],
 )
 
-INFIX_OPERATOR_TO_DECLARATION = {
+FUR_INFIX_OPERATOR_TO_C_FUNCTION = {
+    '++':   'concatenate',
+}
+
+FUR_INFIX_OPERATOR_TO_C_INFIX_OPERATOR = {
     '+':    CInfixDeclaration(name='add', in_type='integer', out_type='integer', operator='+'),
     '-':    CInfixDeclaration(name='subtract', in_type='integer', out_type='integer', operator='-'),
     '*':    CInfixDeclaration(name='multiply', in_type='integer', out_type='integer', operator='*'),
@@ -202,7 +207,7 @@ INFIX_OPERATOR_TO_DECLARATION = {
 }
 
 def transform_comparison_level_expression(accumulators, expression):
-    accumulators.operator_set.add(INFIX_OPERATOR_TO_DECLARATION[expression.operator])
+    accumulators.operator_set.add(FUR_INFIX_OPERATOR_TO_C_INFIX_OPERATOR[expression.operator])
 
     # Transform expressions like 1 < 2 < 3 into expressions like 1 < 2 && 2 < 3
     if isinstance(expression.left, parsing.FurInfixExpression) and expression.left.order == 'comparison_level':
@@ -223,26 +228,35 @@ def transform_comparison_level_expression(accumulators, expression):
             name='and',
             left=left,
             right=CFunctionCallForFurInfixOperator(
-                name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
+                name=FUR_INFIX_OPERATOR_TO_C_INFIX_OPERATOR[expression.operator].name,
                 left=middle,
                 right=right,
             ),
         )
 
     return CFunctionCallForFurInfixOperator(
-        name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
+        name=FUR_INFIX_OPERATOR_TO_C_INFIX_OPERATOR[expression.operator].name,
         left=transform_expression(accumulators, expression.left),
         right=transform_expression(accumulators, expression.right),
     )
 
+def transform_infix_operator_without_c_equivalent(accumulators, expression):
+    return CFunctionCallForFurInfixOperator(
+        name='concatenate',
+        left=transform_expression(accumulators, expression.left),
+        right=transform_expression(accumulators, expression.right),
+    )
 def transform_infix_expression(accumulators, expression):
+    if expression.operator in FUR_INFIX_OPERATOR_TO_C_FUNCTION:
+        return transform_infix_operator_without_c_equivalent(accumulators, expression)
+
     if expression.order == 'comparison_level':
         return transform_comparison_level_expression(accumulators, expression)
 
-    accumulators.operator_set.add(INFIX_OPERATOR_TO_DECLARATION[expression.operator])
+    accumulators.operator_set.add(FUR_INFIX_OPERATOR_TO_C_INFIX_OPERATOR[expression.operator])
 
     return CFunctionCallForFurInfixOperator(
-        name=INFIX_OPERATOR_TO_DECLARATION[expression.operator].name,
+        name=FUR_INFIX_OPERATOR_TO_C_INFIX_OPERATOR[expression.operator].name,
         left=transform_expression(accumulators, expression.left),
         right=transform_expression(accumulators, expression.right),
     )