Merge pull request #77 from rooby-lang/fix-while-syntax

Fix while statement's weird syntax

README.md

@@ -52,18 +52,14 @@ A lot people have questions about `rooby` since it's a new language and you may
     - Array
 - Flow control
     - If statement
-    - while statement with [special syntax](https://github.com/rooby-lang/rooby/wiki/Special-syntaxes)
+    - while statement
 - Import other files
     - require_relative
 - IO
     - `puts`
     - `ARGV`
 
-**(You can open an issue for any feature request)** 
-
-## Special syntax
-
-Currently our parser has some limitation that cause `rooby` unable to support some syntaxes. These special cases are documented in [wiki's special syntax page](https://github.com/rooby-lang/rooby/wiki/Special-syntaxes).
+**(You can open an issue for any feature request)**
 
 ## TODO & WIP
 

benchmarks/million_loop.ro

@@ -1,5 +1,5 @@
 i = 1000000
-while i > 0; do
+while i > 0 do
     i = i - 1
 end
 

bytecode/generator_test.go

@@ -665,7 +665,7 @@ func TestWhileStatementWithMethodCallInCondition(t *testing.T) {
 	i = 10
 	a = [1, 2, 3]
 
-	while i > a.length; do
+	while i > a.length do
 	  i = i - 1
 	end
 

parser/expression_parsing.go

@@ -330,7 +330,7 @@ func (p *Parser) parseCallExpression(receiver ast.Expression) ast.Expression {
 	}
 
 	// Parse block
-	if p.peekTokenIs(token.Do) {
+	if p.peekTokenIs(token.Do) && p.acceptBlock {
 		p.parseBlockParameters(exp)
 	}
 

parser/parser.go

@@ -19,6 +19,11 @@ type Parser struct {
 
 	prefixParseFns map[token.Type]prefixParseFn
 	infixParseFns  map[token.Type]infixParseFn
+
+	// Determine if call expression should accept block argument,
+	// currently only used when parsing while statement.
+	// However, this is not a very good practice should change it in the future.
+	acceptBlock bool
 }
 
 // BuildAST tokenizes and parses given file to build AST
@@ -35,8 +40,9 @@ func BuildAST(file []byte) *ast.Program {
 // New initializes a parser and returns it
 func New(l *lexer.Lexer) *Parser {
 	p := &Parser{
-		l:      l,
-		errors: []string{},
+		l:           l,
+		errors:      []string{},
+		acceptBlock: true,
 	}
 
 	// Read two tokens, so curToken and peekToken are both set.

parser/statement_parsing.go

@@ -239,7 +239,10 @@ func (p *Parser) parseWhileStatement() *ast.WhileStatement {
 	ws := &ast.WhileStatement{Token: p.curToken}
 
 	p.nextToken()
+	// Prevent expression's method call to consume while's block as argument.
+	p.acceptBlock = false
 	ws.Condition = p.parseExpression(LOWEST)
+	p.acceptBlock = true
 	p.nextToken()
 
 	if p.curTokenIs(token.Semicolon) {

parser/statement_parsing_test.go

@@ -330,7 +330,7 @@ func TestRequireRelativeStatement(t *testing.T) {
 
 func TestWhileStatement(t *testing.T) {
 	input := `
-	while i < a.length; do
+	while i < a.length do
 	  puts(i)
 	  i++
 	end

samples/loop.ro

@@ -1,5 +1,5 @@
 i = 0
-while i < 10; do
+while i < 10 do
     i = i + 1
     puts(i)
 end

vm/statement_test.go

@@ -193,7 +193,7 @@ func TestWhileStatement(t *testing.T) {
 			`
 		a = [1, 2, 3, 4, 5]
 		i = 0
-		while i < a.length; do
+		while i < a.length do
 			a[i]++
 			i++
 		end