ADD: if-then-else expression.

src/compiler.c

@@ -24,13 +24,17 @@ void compile_node(compiler* self, node* root, program* prog)
 	assert(root);
 	assert(prog);
 	
-	if (root->type == NODE_DO)
+	if (root->type == NODE_BLOCK)
 	{
 		symtable_enter_scope(self->sym);
 		compile_children(self, root, prog);
 		symtable_leave_scope(self->sym);
 	}
-
+	else if (root->type == NODE_IF)
+	{
+		compile_if(self, root, prog);
+		program_set_mark_params(prog, prog->instrs.size);
+	}
 	else if (root->type == NODE_INDEX)
 	{
 		compile_children(self, root, prog);
@@ -507,6 +511,36 @@ type* compile_get_type(compiler* self, node* root)
 	return ty;
 }
 
+void compile_if(compiler* self, node* root, program* prog)
+{
+	if (root->children.size == 1)
+	{
+		compile_children(self, root, prog);
+		return;
+	}
+
+	// if cond
+	node* cond = root->children.data[0];
+	compile_node(self, cond, prog);
+	size_t const cond_addr = prog->instrs.size;
+	program_add_instr(prog, OP_BRF, 0 /* to next */);
+
+	// then block
+	node* then_block = root->children.data[1];
+	compile_node(self, then_block, prog);
+	program_add_instr(prog, OP_BR, MARK_PARAM);
+
+	// next
+	program_set_instr(prog, cond_addr, OP_BRF, prog->instrs.size);
+	
+	if (root->children.size >= 3)
+	{
+		node* next_node = root->children.data[2];
+		//char c [512]; node_str(next_node, c, 512); printf("=> %s\n", c);
+		compile_if(self, next_node, prog); 
+	}
+}
+
 void compile_number(compiler* self, node* root, program* prog, 
 		int integer_op,
 		int float_op)

src/compiler.h

@@ -22,4 +22,7 @@ type* compile_get_type(compiler* self, node* root);
 void compile_number(compiler* self, node* root, program* prog, 
 		int integer_op,
 		int float_op);
+
+void compile_if(compiler* self, node* root, program* prog);
+
 #endif

src/cstatic.c

@@ -43,6 +43,14 @@ type* cstatic_resolve_new(cstatic* self, symtable* sym, node* ast)
 		return ty;
 	}
 
+	if (ast->type == NODE_IF)
+	{
+		type* ty = cstatic_resolve_new(self, 
+				sym,
+				ast->children.data[1]);
+		return ty;
+	}
+
 	if (ast->type == NODE_DO)
 	{
 		type* ty = cstatic_resolve_new(self, 
@@ -229,8 +237,8 @@ int cstatic_check(cstatic* self, node* ast, symtable* sym, char* msg, size_t siz
 	assert(self);
 	assert(ast);
 	
-	// DO BLOCK
-	if (ast->type == NODE_DO)
+	// BLOCK
+	if (ast->type == NODE_BLOCK)
 	{
 		symtable_enter_scope(sym);
 		
@@ -318,6 +326,26 @@ int cstatic_check(cstatic* self, node* ast, symtable* sym, char* msg, size_t siz
 		
 		return 1;
 	}
+	else if (ast->type == NODE_IF && ast->children.size > 1)
+	{
+		assert(ast->children.size > 0);
+		type* right = cstatic_resolve_new(self, sym, ast->children.data[0]);
+		type* left = cstatic_new_type(self, TY_BOOLEAN);
+
+		int status = cstatic_check_same_type_ptr(
+			self,
+			ast->children.data[0],
+			left, right, sym, msg, size
+		);	
+
+		if (status)
+		{
+			type_free(left); free(left);
+			type_free(right); free(right);
+		}
+
+		return status;
+	}
 	else if (ast->type == NODE_ARRAY)
 	{
 		assert(ast->children.size > 0);

src/lex.l

@@ -25,6 +25,8 @@ IDENT [_A-Za-z][_A-Za-z0-9]*
 	yylval.str = str_new(yytext);
 	return TYPE;
 }
+"if" { return IF_COND; }
+"else" { return ELSE_COND; }
 "is" { return IS; }
 "do" { return DO; }
 "end" { return END; }

src/node.h

@@ -12,7 +12,8 @@
 	G(NODE_MUL), G(NODE_DIV), G(NODE_MOD), G(NODE_POW), \
 	G(NODE_ARRAY), G(NODE_INDEX), G(NODE_LT), G(NODE_LE), \
 	G(NODE_GT), G(NODE_GE), G(NODE_VARDECL), G(NODE_IDENT), \
-	G(NODE_CONSTDECL), G(NODE_ASSIGN), G(NODE_DO), G(NODE_IS)
+	G(NODE_CONSTDECL), G(NODE_ASSIGN), G(NODE_DO), G(NODE_IS), \
+	G(NODE_IF), G(NODE_ELSE), G(NODE_BLOCK)
 
 
 #include "mutils.h"

src/opcodes.h

@@ -45,7 +45,9 @@
 	G(OP_STORE), \
 	G(OP_LOAD), \
 	G(OP_ASTORE), \
-	G(OP_TEQ)
+	G(OP_TEQ), \
+	G(OP_BRF), \
+	G(OP_BR)
 
 
 enum Opcodes {

src/parser.y

@@ -21,10 +21,12 @@
 	size_t n_children;
 };
 
+%token IF_COND
+%token ELSE_COND
 %left ASSERT
 %token <str> TYPE BOOLEAN INTEGER FLOAT STRING IDENT
 %type <n_children> expr exprs prog array builtins
-%type <n_children> expr_list type type_list ident
+%type <n_children> expr_list type type_list ident if 
 %left EQ NE
 %left LT GT LE GE
 %left AND
@@ -36,7 +38,7 @@
 %token OPAR CPAR 
 %token OSQUARE CSQUARE COMMA
 %token LET LET_MUT ASSIGN DO END
-%type <n_children> expr_unop
+%type <n_children> expr_unop block if_rec
 %left IS
 
 %%
@@ -75,6 +77,7 @@ exprs:
 	exprs expr { $$ = $1 + $2; }
 
 	| expr { $$ = $1; }
+	
 ;
 
 
@@ -93,29 +96,19 @@ expr:
 		stack_push(n);
 		$$ = 1;
 	}
+	
+	| if {}
 
     	// BLOCK
-	| DO exprs END {
+	| DO block END {
 		node* n = malloc(sizeof(node));
 		node_init(n, NODE_DO, "", line);
 
-		size_t const SZ = $2;
-		node* all[SZ];
-
-		for (size_t i=0; i<SZ; i++)
-		{
-			all[SZ - 1 - i] = stack_pop();
-		}
-
-		for (size_t i=0; i<SZ; i++)
-		{
-			node_add_child(n, all[i]);
-		}
+		node_add_child(n, stack_pop());
 
 		stack_push(n);
 
 		$$ = 1;
-
 	}
 
     	// INDEX
@@ -391,6 +384,73 @@ expr:
 	
 ;
 
+if_rec:
+	ELSE_COND IF_COND expr block if_rec {
+		node* n = malloc(sizeof(node));
+		node_init(n, NODE_IF, "", line);
+		
+		node* next_node = stack_pop();
+		node* block_node = stack_pop();
+		node* expr_node = stack_pop();
+
+		node_add_child(n, expr_node);
+		node_add_child(n, block_node);
+		node_add_child(n, next_node);
+
+		stack_push(n);
+
+		$$ = 1;
+	}
+
+	| ELSE_COND expr END {
+		node* n = malloc(sizeof(node));
+		node_init(n, NODE_IF, "", line);
+		
+		node* expr_node = stack_pop();
+
+		node_add_child(n, expr_node);
+
+		stack_push(n);
+
+		$$ = 1;
+	}
+;
+
+if:
+	IF_COND expr block if_rec {
+		node* n = malloc(sizeof(node));
+		node_init(n, NODE_IF, "", line);
+		
+		node* rec_node = stack_pop();
+		node* block_node = stack_pop();
+		node* expr_node = stack_pop();
+
+		node_add_child(n, expr_node);
+		node_add_child(n, block_node);
+		node_add_child(n, rec_node);
+
+		stack_push(n);
+
+		$$ = 1;
+	}
+
+	| IF_COND expr block END {
+		node* n = malloc(sizeof(node));
+		node_init(n, NODE_IF, "", line);
+		
+		node* block_node = stack_pop();
+		node* expr_node = stack_pop();
+
+		node_add_child(n, expr_node);
+		node_add_child(n, block_node);
+
+		stack_push(n);
+
+		$$ = 1;
+	}
+	
+;
+
 expr_unop:
 	ADD expr {
 		node *n = malloc(sizeof(node));
@@ -415,6 +475,30 @@ type_list:
 
 ;
 
+block:
+    	exprs {
+		node* n = malloc(sizeof(node));
+		node_init(n, NODE_BLOCK, "", line);
+
+		size_t const SZ = $1;
+		node* all[SZ];
+
+		for (size_t i=0; i<SZ; i++)
+		{
+			all[SZ - 1 - i] = stack_pop();
+		}
+
+		for (size_t i=0; i<SZ; i++)
+		{
+			node_add_child(n, all[i]);
+		}
+
+		stack_push(n);
+
+		$$ = 1;
+	}
+;
+
 type: 	
     	TYPE LT type_list GT {
 		node* n = malloc(sizeof(node));

src/program.c

@@ -37,7 +37,27 @@ void program_free(program* self)
 	self->pool.capacity = 0;
 }
 
-void program_add_instr(program* self, int opcode, int param)
+void program_set_instr(program* self, size_t index, int opcode, int param)
+{
+	assert(self);
+	assert(index < self->instrs.size);
+
+	self->instrs.data[index]->opcode = opcode;
+	self->instrs.data[index]->param = param;
+}
+
+void program_set_mark_params(program* self, int param)
+{
+	for (size_t i=0; i<self->instrs.size; i++)
+	{
+		if (self->instrs.data[i]->param == MARK_PARAM)
+		{
+			self->instrs.data[i]->param = param;
+		}
+	}
+}
+
+size_t program_add_instr(program* self, int opcode, int param)
 {
 	assert(self);
 
@@ -62,6 +82,8 @@ void program_add_instr(program* self, int opcode, int param)
 	self->instrs.data[idx]->param = param;
 
 	self->instrs.size++;
+
+	return self->instrs.size - 1;
 }
 
 size_t program_add_pool(program* self, value* val)

src/program.h

@@ -6,6 +6,7 @@
 #include "value.h"
 
 #define NO_PARAM (-1)
+#define MARK_PARAM (-2)
 
 typedef struct {
 	int opcode;
@@ -29,7 +30,10 @@ typedef struct {
 void program_init(program* self);
 void program_free(program* self);
 
-void program_add_instr(program* self, int opcode, int param);
+size_t program_add_instr(program* self, int opcode, int param);
+void program_set_instr(program* self, size_t index, int opcode, int param);
+void program_set_mark_params(program* self, int param);
+
 size_t program_add_pool(program* self, value* val);
 
 size_t program_str(program* self, char* buffer, size_t size);

src/symtable.c

@@ -47,7 +47,7 @@ size_t symtable_declare_mut(symtable* self, char const* name, type* ty, node* sy
 	assert(self);
 	size_t id = symtable_declare(self, name, ty, sym_node);
 
-	self->entries.data[id]->is_mut = 1;
+	self->entries.data[self->entries.size - 1]->is_mut = 1;
 
 	return id;
 }

src/vm.c

@@ -104,6 +104,9 @@ void vm_exec(vm* self, program* prog)
 			case OP_STORE: vm_store(self, param); break;
 			case OP_ASTORE: vm_astore(self, param); break;
 
+			case OP_BRF: vm_brf(self, param); break;
+			case OP_BR: vm_br(self, param); break;
+
 			case OP_TEQ: vm_teq(self); break;
 
 			default: {
@@ -1117,3 +1120,25 @@ void vm_teq(vm* self)
 	self->pc++;
 }
 
+void vm_brf(vm* self, int param)
+{
+	assert(self);
+	value* val = vm_pop_value(self);
+
+	if (!val->val.boolean)
+	{
+		self->pc = param;
+	}
+	else
+	{
+		self->pc++;
+	}
+
+	value_free(val); free(val);
+}
+
+void vm_br(vm* self, int param)
+{
+	assert(self);
+	self->pc = param;
+}

src/vm.h

@@ -92,4 +92,7 @@ void vm_astore(vm* self, int param);
 
 void vm_teq(vm* self);
 
+void vm_brf(vm* self, int param);
+void vm_br(vm* self, int param);
+
 #endif

tests/err_if.wuz

@@ -0,0 +1,4 @@
+if 4 0 end
+if int 0 end
+if "salut" 0 end
+if 400.7 0 end

tests/test_if.wuz

@@ -0,0 +1,45 @@
+let! a = 0
+let b = 12
+
+if true
+	a = 1
+	let b = 34
+	assert 34 == b
+end
+
+assert 1 == a
+assert 12 == b
+
+
+if false
+	a = 2
+	let b = 76
+	assert 76 == b
+end
+
+assert 1 == a
+assert 12 == b
+
+let! c = 0
+
+if true
+	c = 1
+else
+	c = 2
+end
+
+assert 1 == c
+
+if false
+	c = 3
+else
+	c = 4
+end
+
+assert 4 == c
+
+let d = if true 1 else 2 end
+assert 1 == d
+
+let e = if false 1 else 2 end
+assert 2 == e