Add optional else to if

paked · Mar 22, 2019 · da8ec7f · da8ec7f
1 parent 28dc870
commit da8ec7f
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Showing 8 changed files with 127 additions and 12 deletions.
diff --git a/example.ls b/example.ls
@@ -1,3 +1,4 @@
+/*
 func fib(n number) number {
     if (n == 0 || n == 1) {
         return n
@@ -7,6 +8,30 @@ func fib(n number) number {
 }
 
 n := fib(8);
+*/
 
-n
-log
+n := 2
+
+if n == 0 {
+    g := 2
+
+    g
+    log
+
+    f := 13
+
+    f
+    log
+} else {
+    z := 100
+
+    z
+    log
+}
+
+if n == 2 {
+    t := 33
+
+    t
+    log
+}
diff --git a/src/ast.cpp b/src/ast.cpp
@@ -138,6 +138,7 @@ struct ASTNode_If {
   ASTNode* condition;
 
   ASTNode* block;
+  ASTNode* elseBlock;
 };
 
 struct Parameter {
@@ -354,6 +355,26 @@ ASTNode ast_makeIf(ASTNode condition, ASTNode block) {
   node.cIf.block = (ASTNode*) malloc(sizeof(block));
   *node.cIf.block = block;
 
+  node.cIf.elseBlock = 0;
+
+  return node;
+}
+
+ASTNode ast_makeIf(ASTNode condition, ASTNode block, ASTNode elseBlock) {
+  assert(block.type == AST_NODE_ROOT && elseBlock.type == AST_NODE_ROOT);
+
+  ASTNode node = {};
+  node.type = AST_NODE_IF;
+
+  node.cIf.condition = (ASTNode*) malloc(sizeof(condition));
+  *node.cIf.condition = condition;
+
+  node.cIf.block = (ASTNode*) malloc(sizeof(block));
+  *node.cIf.block = block;
+
+  node.cIf.elseBlock = (ASTNode*) malloc(sizeof(elseBlock));
+  *node.cIf.elseBlock = elseBlock;
+
   return node;
 }
 
@@ -557,15 +578,34 @@ bool ast_writeBytecode(ASTNode* node, Hunk* hunk, Scope* scope) {
         hunk_write(hunk, OP_JUMP_IF_FALSE, 0);
         hunk_write(hunk, 0, 0);
 
-        Instruction offsetPos = hunk_getCount(hunk) - 1;
+        Instruction nextStatementPos = hunk_getCount(hunk) - 1;
 
         if (!ast_writeBytecode(node->cIf.block, hunk, &inner)) {
           return false;
         }
 
-        Instruction ifEndPos = hunk_getCount(hunk) - 1;
+        if (node->cIf.elseBlock != 0) {
+          Scope elseInner = {};
+          scope_init(&elseInner, scope);
+
+          hunk_write(hunk, OP_JUMP, 0);
+          hunk_write(hunk, 0, 0);
+
+          Instruction exitBlockPos = hunk_getCount(hunk) - 1;
+
+          hunk->code[nextStatementPos] = hunk_getCount(hunk) - 1 - nextStatementPos;
 
-        hunk->code[offsetPos] = ifEndPos - offsetPos;
+          if (!ast_writeBytecode(node->cIf.elseBlock, hunk, &elseInner)) {
+            return false;
+          }
+
+          Instruction endOfElsePos = hunk_getCount(hunk) - 1;
+          hunk->code[exitBlockPos] = endOfElsePos - exitBlockPos;
+        } else {
+          Instruction ifEndPos = hunk_getCount(hunk) - 1;
+
+          hunk->code[nextStatementPos] = ifEndPos - nextStatementPos;
+        }
        } break;
     case AST_NODE_NUMBER:
       {

diff --git a/src/bytecode.cpp b/src/bytecode.cpp
@@ -45,6 +45,7 @@ enum OPCode : Instruction {
   OP_TEST_OR,   // ||
   OP_TEST_AND,  // &&
 
+  OP_JUMP,
   OP_JUMP_IF_FALSE,
 
   OP_LOG,
@@ -125,6 +126,7 @@ int hunk_disassembleInstruction(Hunk* hunk, int offset) {
     SIMPLE_INSTRUCTION(OP_TEST_OR);
 
     SIMPLE_INSTRUCTION2(OP_SET_LOCAL);
+    SIMPLE_INSTRUCTION2(OP_JUMP);
     SIMPLE_INSTRUCTION2(OP_JUMP_IF_FALSE);
     SIMPLE_INSTRUCTION2(OP_CALL);
     SIMPLE_INSTRUCTION2(OP_RETURN);
@@ -297,6 +299,8 @@ ProgramResult vm_run(VM* vm) {
           Value name = vm_stack_pop(vm);
 
           if (name.type != VALUE_STRING) {
+            logf("ERROR: Expecting name in string format\n");
+
             return PROGRAM_RESULT_RUNTIME_ERROR;
           }
 
@@ -307,6 +311,8 @@ ProgramResult vm_run(VM* vm) {
           Value name = vm_stack_pop(vm);
 
           if (name.type != VALUE_STRING) {
+            logf("ERROR: Expecting name in string format\n");
+
             return PROGRAM_RESULT_RUNTIME_ERROR;
           }
 
@@ -326,6 +332,8 @@ ProgramResult vm_run(VM* vm) {
           int arity = (int) READ();
 
           if (func.type != VALUE_FUNCTION) {
+            logf("ERROR Expecting func to be a function\n");
+
             return PROGRAM_RESULT_RUNTIME_ERROR;
           }
 
@@ -361,6 +369,12 @@ ProgramResult vm_run(VM* vm) {
             frame->ip += jumpOffset;
           }
         } break;
+      case OP_JUMP:
+        {
+          Instruction jumpOffset = READ();
+
+          frame->ip += jumpOffset;
+        } break;
       case OP_NEGATE:
         {
           Value v = vm_stack_pop(vm);
@@ -401,6 +415,7 @@ ProgramResult vm_run(VM* vm) {
           Value b = vm_stack_pop(vm); \
           Value a = vm_stack_pop(vm); \
           if (!VALUE_IS_NUMBER(a) || !VALUE_IS_NUMBER(b)) { \
+            logf("ERROR: values should be numbers\n");\
             return PROGRAM_RESULT_RUNTIME_ERROR; \
           } \
           Value c = {}; \
@@ -419,6 +434,8 @@ ProgramResult vm_run(VM* vm) {
           Value a = vm_stack_pop(vm);
 
           if (!VALUE_IS_BOOL(a) || !VALUE_IS_BOOL(b)) {
+            logf("ERROR: values should be bools\n");
+
             return PROGRAM_RESULT_RUNTIME_ERROR;
           }
 
@@ -435,6 +452,8 @@ ProgramResult vm_run(VM* vm) {
           Value a = vm_stack_pop(vm);
 
           if (!VALUE_IS_BOOL(a) || !VALUE_IS_BOOL(b)) {
+            logf("ERROR: values should be bools\n");
+
             return PROGRAM_RESULT_RUNTIME_ERROR;
           }
 

diff --git a/src/lexer.cpp b/src/lexer.cpp
@@ -15,6 +15,7 @@ enum TokenType : uint32 {
   TOKEN_FALSE,
 
   TOKEN_IF,
+  TOKEN_ELSE,
   TOKEN_FUNC,
   TOKEN_RETURN,
   TOKEN_VAR,
@@ -140,6 +141,7 @@ Token scanner_readIdentifier(Scanner* scn) {
   // true
   // false
   // if
+  // else
   // func
   // var
   // return
@@ -148,6 +150,8 @@ Token scanner_readIdentifier(Scanner* scn) {
       t.type = TOKEN_TRUE;
     } else if (strncmp(t.start, "func", 4) == 0) {
       t.type = TOKEN_FUNC;
+    } else if (strncmp(t.start, "else", 4) == 0) {
+      t.type = TOKEN_ELSE;
     }
   } else if (t.len == 5) {
     if (strncmp(t.start, "false", 5) == 0) {

diff --git a/src/main.cpp b/src/main.cpp
@@ -113,6 +113,10 @@ int main(int argc, char** argv) {
   hunk_write(&hunk, OP_RETURN, 0);
   hunk_write(&hunk, 0, 0);
 
+#ifdef DEBUG
+  hunk_disassemble(&hunk, "main");
+#endif
+
   VM vm = {0};
 
   vm_load(&vm, &hunk);

diff --git a/src/parser.cpp b/src/parser.cpp
@@ -337,9 +337,19 @@ bool parser_parseIf(Parser* p, ASTNode* node) {
         ASTNode block = {};
 
         if (parser_parseBlock(p, &block)) {
-          *node = ast_makeIf(condition, block);
+          if (parser_expect(p, TOKEN_ELSE)) {
+            ASTNode elseBlock = {};
 
-          return true;
+            if (parser_parseBlock(p, &elseBlock)) {
+              *node = ast_makeIf(condition, block, elseBlock);
+
+              return true;
+            }
+          } else {
+            *node = ast_makeIf(condition, block);
+
+            return true;
+          }
         }
       }
   }

diff --git a/src/typing.cpp b/src/typing.cpp
@@ -561,10 +561,25 @@ bool typeCheck(ASTNode* node, SymbolTable* symbols) {
           return false;
         }
 
-        SymbolTable childSymbols = {};
-        symbolTable_init(&childSymbols, symbols);
+        {
+          SymbolTable childSymbols = {};
+          symbolTable_init(&childSymbols, symbols);
+
+          if (!typeCheck(node->cIf.block, &childSymbols)) {
+            return false;
+          }
+        }
 
-        return typeCheck(node->cIf.block, &childSymbols);
+        if (node->cIf.elseBlock != 0) {
+          SymbolTable childSymbols = {};
+          symbolTable_init(&childSymbols, symbols);
+
+          if (!typeCheck(node->cIf.elseBlock, &childSymbols)) {
+            return false;
+          }
+        }
+
+        return true;
       } break;
     case AST_NODE_RETURN:
       {

diff --git a/src/value.cpp b/src/value.cpp
@@ -166,5 +166,3 @@ bool value_equals(Value left, Value right) {
 
   return false;
 }
-
-
Original file line number	Diff line number	Diff line change
Expand Up		@@ -166,5 +166,3 @@ bool value_equals(Value left, Value right) {

		return false;
		}