add: Add continue statement

Interpreter/interpreter.go

@@ -263,6 +263,11 @@ func (i *Interpreter) VisitLogicalExpr(expr ast.Logical) interface{} {
 func (i *Interpreter) VisitWhileStmtStmt(stmt ast.WhileStmt) interface{} {
 	for i.isTruthy(i.evaluate(stmt.Condition)) {
 		i.execute(stmt.Body)
+
+		if state.ContinueException {
+			state.ContinueException = false
+			continue
+		}
 		if state.AbruptCompletion {
 			state.AbruptCompletion = false
 			break
@@ -281,8 +286,11 @@ func (i *Interpreter) executeBlock(statements []ast.Stmt, environment *environme
 	i.Environment = environment
 	for _, stmt := range statements {
 		i.execute(stmt)
+		if state.ContinueException {
+			return // Exit the block immediately for continue, let while loop handle the flag
+		}
 		if state.AbruptCompletion {
-			break
+			return // Exit the block immediately for break, let while loop handle the flag
 		}
 	}
 }
@@ -291,3 +299,8 @@ func (i *Interpreter) VisitBreakStmtStmt(stmt ast.BreakStmt) interface{} {
 	state.AbruptCompletion = true
 	return nil
 }
+
+func (i *Interpreter) VisitContinueStmtStmt(stmt ast.ContinueStmt) interface{} {
+	state.ContinueException = true
+	return nil
+}

Scanner/scanner.go

@@ -20,23 +20,24 @@ type Scanner struct {
 }
 
 var KeywordMap = map[string]token.TokenType{
-	"and":    token.AND,
-	"class":  token.CLASS,
-	"else":   token.ELSE,
-	"false":  token.FALSE,
-	"for":    token.FOR,
-	"fun":    token.FUN,
-	"if":     token.IF,
-	"nil":    token.NIL,
-	"or":     token.OR,
-	"print":  token.PRINT,
-	"return": token.RETURN,
-	"super":  token.SUPER,
-	"this":   token.THIS,
-	"true":   token.TRUE,
-	"var":    token.VAR,
-	"while":  token.WHILE,
-	"break":  token.BREAK,
+	"and":      token.AND,
+	"class":    token.CLASS,
+	"else":     token.ELSE,
+	"false":    token.FALSE,
+	"for":      token.FOR,
+	"fun":      token.FUN,
+	"if":       token.IF,
+	"nil":      token.NIL,
+	"or":       token.OR,
+	"print":    token.PRINT,
+	"return":   token.RETURN,
+	"super":    token.SUPER,
+	"this":     token.THIS,
+	"true":     token.TRUE,
+	"var":      token.VAR,
+	"while":    token.WHILE,
+	"break":    token.BREAK,
+	"continue": token.CONTINUE,
 }
 
 func (s *Scanner) isAtEnd() bool {

Token/token.go

@@ -54,6 +54,7 @@ const (
 	VAR
 	WHILE
 	BREAK
+	CONTINUE
 
 	// End of file
 	EOF
@@ -67,7 +68,7 @@ func (t TokenType) String() string {
 		"LESS", "LESS_EQUAL",
 		"IDENTIFIER", "STRING", "NUMBER",
 		"AND", "CLASS", "ELSE", "FALSE", "FUN", "FOR", "IF", "NIL", "OR",
-		"PRINT", "RETURN", "SUPER", "THIS", "TRUE", "VAR", "WHILE", "BREAK",
+		"PRINT", "RETURN", "SUPER", "THIS", "TRUE", "VAR", "WHILE", "BREAK", "CONTINUE",
 		"EOF",
 	}[t]
 }

ast/stmt.go

@@ -12,6 +12,7 @@ type StmtVisitor interface {
     VisitVarStmtStmt(stmt VarStmt) interface{}
     VisitWhileStmtStmt(stmt WhileStmt) interface{}
     VisitBreakStmtStmt(stmt BreakStmt) interface{}
+    VisitContinueStmtStmt(stmt ContinueStmt) interface{}
 }
 
 type Stmt interface {
@@ -77,3 +78,10 @@ func (n BreakStmt) Accept(visitor StmtVisitor) interface{} {
     return visitor.VisitBreakStmtStmt(n)
 }
 
+type ContinueStmt struct {
+}
+
+func (n ContinueStmt) Accept(visitor StmtVisitor) interface{} {
+    return visitor.VisitContinueStmtStmt(n)
+}
+

parser/parser.go

@@ -273,6 +273,9 @@ func (p *Parser) statement() ast.Stmt {
 	if p.match(token.PRINT) {
 		return p.printStatement()
 	}
+	if p.match(token.CONTINUE) {
+		return p.continueStatement()
+	}
 	if p.match(token.BREAK) {
 		return p.breakStatement()
 	}
@@ -310,9 +313,9 @@ func (p *Parser) forStatement() ast.Stmt {
 	}
 	p.consume(token.RIGHT_PAREN, "Expect ')' after for clauses.")
 
-	state.CanInsertBreakStatement = true
+	state.CanInsertBreakOrContinueStatement = true
 	body := p.statement()
-	state.CanInsertBreakStatement = false
+	state.CanInsertBreakOrContinueStatement = false
 
 	if increment != nil {
 		body = ast.BlockStmt{
@@ -367,18 +370,26 @@ func (p *Parser) whileStatement() ast.Stmt {
 	condition := p.expression()
 	p.consume(token.RIGHT_PAREN, "Expect ')' after condition.")
 
-	state.CanInsertBreakStatement = true
+	state.CanInsertBreakOrContinueStatement = true
 	body := p.statement()
-	state.CanInsertBreakStatement = false
+	state.CanInsertBreakOrContinueStatement = false
 	return ast.WhileStmt{
 		Condition: condition,
 		Body:      body,
 	}
 
 }
+func (p *Parser) continueStatement() ast.Stmt {
+	if !state.CanInsertBreakOrContinueStatement {
+		p.error(p.peek(), "continueStatemen can only exist inside valid iterator")
+
+	}
+	p.consume(token.SEMICOLON, "Expect ';' after value.")
+	return ast.ContinueStmt{}
+}
 
 func (p *Parser) breakStatement() ast.Stmt {
-	if !state.CanInsertBreakStatement {
+	if !state.CanInsertBreakOrContinueStatement {
 		p.error(p.peek(), "breakStatement can only exist inside valid iterator")
 
 	}

printer/generateAst.go

@@ -126,5 +126,6 @@ func main() {
 		"VarStmt : token.Token name, Expr initializer",
 		"WhileStmt: Expr condition, Stmt body",
 		"BreakStmt: ",
+		"ContinueStmt: ",
 	}, []string{"github.com/shubhdevelop/YAPL/Token"})
 }

state/state.go

@@ -2,5 +2,6 @@ package state
 
 var HadError bool = false
 var HadRuntimeError = false
-var CanInsertBreakStatement = false
+var CanInsertBreakOrContinueStatement = false
 var AbruptCompletion = false
+var ContinueException = false