From e7a7d05e64aebaa0a56d5c0d17f78b45cc62f7af Mon Sep 17 00:00:00 2001
From: Sky Johnson <skylearj@gmail.com>
Date: Tue, 10 Jun 2025 11:54:17 -0500
Subject: [PATCH] add break and exit, remove var

---
 parser/ast.go                  |  22 ++
 parser/parser.go               |  45 +++-
 parser/tests/breakexit_test.go | 428 +++++++++++++++++++++++++++++++++
 parser/token.go                |   6 +-
 4 files changed, 496 insertions(+), 5 deletions(-)
 create mode 100644 parser/tests/breakexit_test.go

diff --git a/parser/ast.go b/parser/ast.go
index 602fd19..8d789be 100644
--- a/parser/ast.go
+++ b/parser/ast.go
@@ -22,6 +22,7 @@ type Expression interface {
 // Program represents the root of the AST
 type Program struct {
 	Statements []Statement
+	ExitCode   int
 }
 
 func (p *Program) String() string {
@@ -53,6 +54,27 @@ func (es *EchoStatement) String() string {
 	return fmt.Sprintf("echo %s", es.Value.String())
 }
 
+// BreakStatement represents break statements to exit loops
+type BreakStatement struct{}
+
+func (bs *BreakStatement) statementNode() {}
+func (bs *BreakStatement) String() string {
+	return "break"
+}
+
+// ExitStatement represents exit statements to quit the script
+type ExitStatement struct {
+	Value Expression // optional, can be nil
+}
+
+func (es *ExitStatement) statementNode() {}
+func (es *ExitStatement) String() string {
+	if es.Value == nil {
+		return "exit"
+	}
+	return fmt.Sprintf("exit %s", es.Value.String())
+}
+
 // ElseIfClause represents an elseif condition
 type ElseIfClause struct {
 	Condition Expression
diff --git a/parser/parser.go b/parser/parser.go
index 74f3900..33409ef 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -117,6 +117,10 @@ func (p *Parser) parseStatement() Statement {
 		return p.parseWhileStatement()
 	case ECHO:
 		return p.parseEchoStatement()
+	case BREAK:
+		return p.parseBreakStatement()
+	case EXIT:
+		return p.parseExitStatement()
 	case ASSIGN:
 		p.addError("assignment operator '=' without left-hand side identifier")
 		return nil
@@ -187,6 +191,39 @@ func (p *Parser) parseEchoStatement() *EchoStatement {
 	return stmt
 }
 
+// parseBreakStatement parses break statements
+func (p *Parser) parseBreakStatement() *BreakStatement {
+	return &BreakStatement{}
+}
+
+// parseExitStatement parses exit statements
+func (p *Parser) parseExitStatement() *ExitStatement {
+	stmt := &ExitStatement{}
+
+	// Check if there's an optional expression after 'exit'
+	// Only parse expression if next token can start an expression
+	if p.canStartExpression(p.peekToken.Type) {
+		p.nextToken() // move past 'exit'
+		stmt.Value = p.ParseExpression(LOWEST)
+		if stmt.Value == nil {
+			p.addError("expected expression after 'exit'")
+			return nil
+		}
+	}
+
+	return stmt
+}
+
+// canStartExpression checks if a token type can start an expression
+func (p *Parser) canStartExpression(tokenType TokenType) bool {
+	switch tokenType {
+	case IDENT, NUMBER, STRING, TRUE, FALSE, NIL, LPAREN, LBRACE, MINUS:
+		return true
+	default:
+		return false
+	}
+}
+
 // parseWhileStatement parses while loops: while condition do ... end
 func (p *Parser) parseWhileStatement() *WhileStatement {
 	stmt := &WhileStatement{}
@@ -739,7 +776,7 @@ func (p *Parser) expectPeekIdent() bool {
 // isKeyword checks if a token type is a keyword that can be used as identifier
 func (p *Parser) isKeyword(t TokenType) bool {
 	switch t {
-	case TRUE, FALSE, NIL, VAR, IF, THEN, ELSEIF, ELSE, END, ECHO, FOR, WHILE, IN, DO:
+	case TRUE, FALSE, NIL, IF, THEN, ELSEIF, ELSE, END, ECHO, FOR, WHILE, IN, DO, BREAK, EXIT:
 		return true
 	default:
 		return false
@@ -873,8 +910,6 @@ func tokenTypeString(t TokenType) string {
 		return "]"
 	case COMMA:
 		return ","
-	case VAR:
-		return "var"
 	case IF:
 		return "if"
 	case THEN:
@@ -895,6 +930,10 @@ func tokenTypeString(t TokenType) string {
 		return "in"
 	case DO:
 		return "do"
+	case BREAK:
+		return "break"
+	case EXIT:
+		return "exit"
 	case EOF:
 		return "end of file"
 	case ILLEGAL:
diff --git a/parser/tests/breakexit_test.go b/parser/tests/breakexit_test.go
new file mode 100644
index 0000000..f31f594
--- /dev/null
+++ b/parser/tests/breakexit_test.go
@@ -0,0 +1,428 @@
+package parser_test
+
+import (
+	"strings"
+	"testing"
+
+	"git.sharkk.net/Sharkk/Mako/parser"
+)
+
+func TestBreakStatement(t *testing.T) {
+	tests := []struct {
+		input string
+		desc  string
+	}{
+		{"break", "standalone break"},
+		{"while true do\nbreak\nend", "break in while loop"},
+		{"for i = 1, 10 do\nbreak\nend", "break in numeric for loop"},
+		{"for k, v in table do\nbreak\nend", "break in for-in loop"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			l := parser.NewLexer(tt.input)
+			p := parser.NewParser(l)
+			program := p.ParseProgram()
+			checkParserErrors(t, p)
+
+			found := false
+			for _, stmt := range program.Statements {
+				if _, ok := stmt.(*parser.BreakStatement); ok {
+					found = true
+					break
+				}
+				// Check nested statements in loops
+				if whileStmt, ok := stmt.(*parser.WhileStatement); ok {
+					for _, bodyStmt := range whileStmt.Body {
+						if _, ok := bodyStmt.(*parser.BreakStatement); ok {
+							found = true
+							break
+						}
+					}
+				}
+				if forStmt, ok := stmt.(*parser.ForStatement); ok {
+					for _, bodyStmt := range forStmt.Body {
+						if _, ok := bodyStmt.(*parser.BreakStatement); ok {
+							found = true
+							break
+						}
+					}
+				}
+				if forInStmt, ok := stmt.(*parser.ForInStatement); ok {
+					for _, bodyStmt := range forInStmt.Body {
+						if _, ok := bodyStmt.(*parser.BreakStatement); ok {
+							found = true
+							break
+						}
+					}
+				}
+			}
+
+			if !found {
+				t.Error("expected to find BreakStatement")
+			}
+		})
+	}
+}
+
+func TestBreakStringRepresentation(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+		desc     string
+	}{
+		{"break", "break", "simple break"},
+		{"while true do\nbreak\nend", "while true do\n\tbreak\nend", "break in while"},
+		{"for i = 1, 10 do\necho i\nbreak\nend", "for i = 1.00, 10.00 do\n\techo i\n\tbreak\nend", "break with other statements"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			l := parser.NewLexer(tt.input)
+			p := parser.NewParser(l)
+			program := p.ParseProgram()
+			checkParserErrors(t, p)
+
+			result := strings.TrimSpace(program.String())
+			if result != tt.expected {
+				t.Errorf("expected %q, got %q", tt.expected, result)
+			}
+		})
+	}
+}
+
+func TestExitStatement(t *testing.T) {
+	tests := []struct {
+		input    string
+		hasValue bool
+		desc     string
+	}{
+		{"exit", false, "exit without value"},
+		{"exit 0", true, "exit with number"},
+		{"exit 1", true, "exit with error code"},
+		{"exit \"success\"", true, "exit with string"},
+		{"exit x", true, "exit with variable"},
+		{"exit 1 + 2", true, "exit with expression"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			l := parser.NewLexer(tt.input)
+			p := parser.NewParser(l)
+			program := p.ParseProgram()
+			checkParserErrors(t, p)
+
+			if len(program.Statements) != 1 {
+				t.Fatalf("expected 1 statement, got %d", len(program.Statements))
+			}
+
+			stmt, ok := program.Statements[0].(*parser.ExitStatement)
+			if !ok {
+				t.Fatalf("expected ExitStatement, got %T", program.Statements[0])
+			}
+
+			if tt.hasValue && stmt.Value == nil {
+				t.Error("expected exit value but got nil")
+			}
+
+			if !tt.hasValue && stmt.Value != nil {
+				t.Error("expected no exit value but got one")
+			}
+		})
+	}
+}
+
+func TestExitStringRepresentation(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+		desc     string
+	}{
+		{"exit", "exit", "simple exit"},
+		{"exit 0", "exit 0.00", "exit with number"},
+		{"exit \"message\"", "exit \"message\"", "exit with string"},
+		{"exit x + 1", "exit (x + 1.00)", "exit with expression"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			l := parser.NewLexer(tt.input)
+			p := parser.NewParser(l)
+			program := p.ParseProgram()
+			checkParserErrors(t, p)
+
+			result := strings.TrimSpace(program.String())
+			if result != tt.expected {
+				t.Errorf("expected %q, got %q", tt.expected, result)
+			}
+		})
+	}
+}
+
+func TestNestedBreakInComplexLoops(t *testing.T) {
+	input := `for i = 1, 10 do
+	while condition do
+		if found then
+			break
+		end
+		x = x + 1
+	end
+	for k, v in data do
+		if v == target then
+			break
+		end
+	end
+end`
+
+	l := parser.NewLexer(input)
+	p := parser.NewParser(l)
+	program := p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if len(program.Statements) != 1 {
+		t.Fatalf("expected 1 statement, got %d", len(program.Statements))
+	}
+
+	outerFor, ok := program.Statements[0].(*parser.ForStatement)
+	if !ok {
+		t.Fatalf("expected ForStatement, got %T", program.Statements[0])
+	}
+
+	if len(outerFor.Body) != 2 {
+		t.Fatalf("expected 2 body statements, got %d", len(outerFor.Body))
+	}
+
+	// First: while loop with break
+	whileStmt, ok := outerFor.Body[0].(*parser.WhileStatement)
+	if !ok {
+		t.Fatalf("expected WhileStatement, got %T", outerFor.Body[0])
+	}
+
+	// Check that while body contains if with break
+	ifStmt, ok := whileStmt.Body[0].(*parser.IfStatement)
+	if !ok {
+		t.Fatalf("expected IfStatement in while body, got %T", whileStmt.Body[0])
+	}
+
+	_, ok = ifStmt.Body[0].(*parser.BreakStatement)
+	if !ok {
+		t.Fatalf("expected BreakStatement in if body, got %T", ifStmt.Body[0])
+	}
+
+	// Second: for-in loop with break
+	forInStmt, ok := outerFor.Body[1].(*parser.ForInStatement)
+	if !ok {
+		t.Fatalf("expected ForInStatement, got %T", outerFor.Body[1])
+	}
+
+	// Check that for-in body contains if with break
+	ifStmt2, ok := forInStmt.Body[0].(*parser.IfStatement)
+	if !ok {
+		t.Fatalf("expected IfStatement in for-in body, got %T", forInStmt.Body[0])
+	}
+
+	_, ok = ifStmt2.Body[0].(*parser.BreakStatement)
+	if !ok {
+		t.Fatalf("expected BreakStatement in if body, got %T", ifStmt2.Body[0])
+	}
+}
+
+func TestExitInMixedProgram(t *testing.T) {
+	input := `x = 42
+if x > 50 then
+	exit 1
+else
+	echo "continuing"
+end
+y = "done"
+exit "success"`
+
+	l := parser.NewLexer(input)
+	p := parser.NewParser(l)
+	program := p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if len(program.Statements) != 4 {
+		t.Fatalf("expected 4 statements, got %d", len(program.Statements))
+	}
+
+	// First: assignment
+	_, ok := program.Statements[0].(*parser.AssignStatement)
+	if !ok {
+		t.Fatalf("statement 0: expected AssignStatement, got %T", program.Statements[0])
+	}
+
+	// Second: if statement with exit in body
+	ifStmt, ok := program.Statements[1].(*parser.IfStatement)
+	if !ok {
+		t.Fatalf("statement 1: expected IfStatement, got %T", program.Statements[1])
+	}
+
+	_, ok = ifStmt.Body[0].(*parser.ExitStatement)
+	if !ok {
+		t.Fatalf("if body: expected ExitStatement, got %T", ifStmt.Body[0])
+	}
+
+	// Third: assignment
+	_, ok = program.Statements[2].(*parser.AssignStatement)
+	if !ok {
+		t.Fatalf("statement 2: expected AssignStatement, got %T", program.Statements[2])
+	}
+
+	// Fourth: final exit
+	_, ok = program.Statements[3].(*parser.ExitStatement)
+	if !ok {
+		t.Fatalf("statement 3: expected ExitStatement, got %T", program.Statements[3])
+	}
+}
+
+func TestExitWithComplexExpressions(t *testing.T) {
+	tests := []struct {
+		input string
+		desc  string
+	}{
+		{"exit table.errorCode", "exit with member access"},
+		{"exit arr[0]", "exit with index access"},
+		{"exit status + 1", "exit with arithmetic"},
+		{"exit {code = 1, msg = \"error\"}", "exit with table"},
+		{"exit obj.nested.value", "exit with chained access"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			l := parser.NewLexer(tt.input)
+			p := parser.NewParser(l)
+			program := p.ParseProgram()
+			checkParserErrors(t, p)
+
+			if len(program.Statements) != 1 {
+				t.Fatalf("expected 1 statement, got %d", len(program.Statements))
+			}
+
+			stmt, ok := program.Statements[0].(*parser.ExitStatement)
+			if !ok {
+				t.Fatalf("expected ExitStatement, got %T", program.Statements[0])
+			}
+
+			if stmt.Value == nil {
+				t.Error("expected exit value but got nil")
+			}
+		})
+	}
+}
+
+func TestControlFlowErrors(t *testing.T) {
+	tests := []struct {
+		input         string
+		expectedError string
+		desc          string
+	}{
+		{"break x", "unexpected identifier", "break with argument"},
+		{"exit +", "unexpected token '+'", "exit with invalid expression"},
+		{"exit (", "unexpected end of input", "exit with incomplete expression"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			l := parser.NewLexer(tt.input)
+			p := parser.NewParser(l)
+			p.ParseProgram()
+
+			if !p.HasErrors() {
+				t.Fatal("expected parsing errors")
+			}
+
+			errors := p.Errors()
+			found := false
+			for _, err := range errors {
+				if strings.Contains(err.Message, tt.expectedError) {
+					found = true
+					break
+				}
+			}
+
+			if !found {
+				errorMsgs := make([]string, len(errors))
+				for i, err := range errors {
+					errorMsgs[i] = err.Message
+				}
+				t.Errorf("expected error containing %q, got %v", tt.expectedError, errorMsgs)
+			}
+		})
+	}
+}
+
+func TestProgramExitCode(t *testing.T) {
+	input := `x = 42
+echo x`
+
+	l := parser.NewLexer(input)
+	p := parser.NewParser(l)
+	program := p.ParseProgram()
+	checkParserErrors(t, p)
+
+	// Program should have default exit code of 0
+	if program.ExitCode != 0 {
+		t.Errorf("expected default exit code 0, got %d", program.ExitCode)
+	}
+}
+
+func TestBreakAndExitInSameProgram(t *testing.T) {
+	input := `for i = 1, 100 do
+	if i == 10 then
+		break
+	end
+	if i > 50 then
+		exit 1
+	end
+	echo i
+end
+exit "completed"`
+
+	l := parser.NewLexer(input)
+	p := parser.NewParser(l)
+	program := p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if len(program.Statements) != 2 {
+		t.Fatalf("expected 2 statements, got %d", len(program.Statements))
+	}
+
+	// First: for loop with break and exit
+	forStmt, ok := program.Statements[0].(*parser.ForStatement)
+	if !ok {
+		t.Fatalf("statement 0: expected ForStatement, got %T", program.Statements[0])
+	}
+
+	if len(forStmt.Body) != 3 {
+		t.Fatalf("expected 3 body statements, got %d", len(forStmt.Body))
+	}
+
+	// Check for break in first if
+	if1, ok := forStmt.Body[0].(*parser.IfStatement)
+	if !ok {
+		t.Fatalf("body[0]: expected IfStatement, got %T", forStmt.Body[0])
+	}
+
+	_, ok = if1.Body[0].(*parser.BreakStatement)
+	if !ok {
+		t.Fatalf("if1 body: expected BreakStatement, got %T", if1.Body[0])
+	}
+
+	// Check for exit in second if
+	if2, ok := forStmt.Body[1].(*parser.IfStatement)
+	if !ok {
+		t.Fatalf("body[1]: expected IfStatement, got %T", forStmt.Body[1])
+	}
+
+	_, ok = if2.Body[0].(*parser.ExitStatement)
+	if !ok {
+		t.Fatalf("if2 body: expected ExitStatement, got %T", if2.Body[0])
+	}
+
+	// Second: final exit
+	_, ok = program.Statements[1].(*parser.ExitStatement)
+	if !ok {
+		t.Fatalf("statement 1: expected ExitStatement, got %T", program.Statements[1])
+	}
+}
diff --git a/parser/token.go b/parser/token.go
index f5b0faa..b61a3b9 100644
--- a/parser/token.go
+++ b/parser/token.go
@@ -38,7 +38,6 @@ const (
 	COMMA    // ,
 
 	// Keywords
-	VAR
 	IF
 	THEN
 	ELSEIF
@@ -49,6 +48,8 @@ const (
 	WHILE
 	IN
 	DO
+	BREAK
+	EXIT
 
 	// Special
 	EOF
@@ -97,7 +98,6 @@ var precedences = map[TokenType]Precedence{
 // lookupIdent checks if an identifier is a keyword
 func lookupIdent(ident string) TokenType {
 	keywords := map[string]TokenType{
-		"var":    VAR,
 		"true":   TRUE,
 		"false":  FALSE,
 		"nil":    NIL,
@@ -111,6 +111,8 @@ func lookupIdent(ident string) TokenType {
 		"while":  WHILE,
 		"in":     IN,
 		"do":     DO,
+		"break":  BREAK,
+		"exit":   EXIT,
 	}
 
 	if tok, ok := keywords[ident]; ok {