make curly braces optional (#42)

* make curly braces optional

Signed-off-by: Flipez <code@brauser.io>

* update docs

Signed-off-by: Flipez <code@brauser.io>

ast/ast.go

@@ -242,15 +242,16 @@ func (ie *IfExpression) TokenLiteral() string { return ie.Token.Literal }
 func (ie *IfExpression) String() string {
 	var out bytes.Buffer
 
-	out.WriteString("if")
+	out.WriteString("if ")
 	out.WriteString(ie.Condition.String())
 	out.WriteString(" ")
 	out.WriteString(ie.Consequence.String())
 
 	if ie.Alternative != nil {
-		out.WriteString("else ")
+		out.WriteString(" else ")
 		out.WriteString(ie.Alternative.String())
 	}
+	out.WriteString(" end")
 
 	return out.String()
 }

docs/content/en/docs/control_expressions/if.md

@@ -13,6 +13,19 @@ With `if` and `else` keywords the flow of a program can be controlled.
   puts("is not a string")
 }
 
+// which prints
+is a string
+```
+
+{{< alert icon="👉" text="Since `0.13` curly braces are completely optional (closing brace needs to be replaced with `end`" />}}
+
+```js
+🚀 > if (a.type() == "STRING")
+  puts("is a string")
+else
+  puts("is not a string")
+end
+
 // which prints
 is a string
 ```

docs/content/en/docs/home.md

@@ -16,9 +16,9 @@ input = a
 
 increase = 0
 foreach i, number in input {
-  if (number > input[i-1]) {
+  if (number > input[i-1])
     increase = increase + 1
-  }
+  end
 }
 puts(increase + 1)
 
@@ -27,9 +27,9 @@ foreach i, number in input {
   sum = number + input[i+1] + input[i+2]
   sum_two = input[i+1] + input[i+2] + input[i+3]
 
-  if (sum_two > sum) {
+  if (sum_two > sum)
     increase = increase + 1
-  }
+  end
 }
 puts(increase + 1)
 ```

docs/content/en/docs/specification/functions.md

@@ -9,15 +9,15 @@ Implicit and explicit return statements are supported.
 
 ```js
 fibonacci = def (x) {
-  if (x == 0) {
+  if (x == 0)
     0
-  } else {
-    if (x == 1) {
+  else
+    if (x == 1)
       return 1;
-    } else {
+    else
       fibonacci(x - 1) + fibonacci(x - 2);
-    }
-  }
+    end
+  end
 };
 ```
 

evaluator/evaluator.go

@@ -333,7 +333,6 @@ func evalIfExpression(ie *ast.IfExpression, env *object.Environment) object.Obje
 	if isError(condition) {
 		return condition
 	}
-
 	if isTruthy(condition) {
 		return Eval(ie.Consequence, env)
 	} else if ie.Alternative != nil {

evaluator/evaluator_test.go

@@ -94,11 +94,15 @@ func TestIfElseExpressions(t *testing.T) {
 	}{
 		{"if (true) { 10 }", 10},
 		{"if (false) { 10 }", nil},
+		{"if (true)\n 10 end", 10},
+		{"if (false) \n 10 end", nil},
 		{"if (1) { 10 }", 10},
+		{"if (1) \n 10 end", 10},
 		{"if (1 < 2) { 10 }", 10},
 		{"if (1 > 2) { 10 }", nil},
 		{"if (1 > 2) { 10 } else { 20 }", 20},
 		{"if (1 < 2) { 10 } else { 20 }", 10},
+		{"if (1 < 2) \n 10 \n else \n 20 end", 10},
 	}
 
 	for _, tt := range tests {

examples/aoc/2021/day-2/complete.rl

@@ -7,18 +7,18 @@ aim = 0
 foreach i, line in input {
   command = line.split(" ")[0]
   value = line.strip().split(" ")[1].plz_i()
-  if (command == "forward") {
+  if (command == "forward")
     hor = hor + value
     depth = depth + (value * aim)
-  }
+  end
 
-  if (command == "down") {
+  if (command == "down")
     aim = aim + value
-  }
+  end
 
- if (command == "up") {
+  if (command == "up")
     aim = aim - value
-  }
+  end
 }
 
 puts(hor * depth)

examples/misc/if.rl

@@ -0,0 +1,15 @@
+if (false)
+  puts("true1")
+else
+  puts("false1")
+end
+
+if (true)
+  puts("true2")
+else
+  puts("false2")
+end
+
+if (true)
+  puts("true3")
+end

parser/parser.go

@@ -400,7 +400,6 @@ func (p *Parser) parseGroupedExpression() ast.Expression {
 
 func (p *Parser) parseIfExpression() ast.Expression {
 	expression := &ast.IfExpression{Token: p.curToken}
-
 	if !p.expectPeek(token.LPAREN) {
 		return nil
 	}
@@ -412,22 +411,22 @@ func (p *Parser) parseIfExpression() ast.Expression {
 		return nil
 	}
 
-	if !p.expectPeek(token.LBRACE) {
-		return nil
+	if p.peekTokenIs(token.LBRACE) {
+		p.nextToken()
 	}
-
 	expression.Consequence = p.parseBlockStatement()
 
-	if p.peekTokenIs(token.ELSE) {
+	if p.curTokenIs(token.RBRACE) {
 		p.nextToken()
+	}
 
-		if !p.expectPeek(token.LBRACE) {
-			return nil
-		}
+	if p.curTokenIs(token.ELSE) {
 
+		if p.peekTokenIs(token.LBRACE) {
+			p.nextToken()
+		}
 		expression.Alternative = p.parseBlockStatement()
 	}
-
 	return expression
 }
 
@@ -437,7 +436,7 @@ func (p *Parser) parseBlockStatement() *ast.BlockStatement {
 
 	p.nextToken()
 
-	for !p.curTokenIs(token.RBRACE) && !p.curTokenIs(token.EOF) {
+	for !p.curTokenIs(token.RBRACE) && !p.curTokenIs(token.EOF) && !p.curTokenIs(token.END) && !p.curTokenIs(token.ELSE) {
 		stmt := p.parseStatement()
 		if stmt != nil {
 			block.Statements = append(block.Statements, stmt)

token/token.go

@@ -43,6 +43,7 @@ const (
 	FALSE    = "FALSE"
 	IF       = "IF"
 	ELSE     = "ELSE"
+	END      = "END"
 	RETURN   = "RETURN"
 
 	EQ     = "=="
@@ -62,6 +63,7 @@ var keywords = map[string]TokenType{
 	"true":    TRUE,
 	"false":   FALSE,
 	"if":      IF,
+	"end":     END,
 	"else":    ELSE,
 	"return":  RETURN,
 	"foreach": FOREACH,