added statement parsing, missing tests and expression

ast/ast.go

@@ -34,6 +34,29 @@ func (t Type) String() string {
 	return string(t)
 }
 
+type Program struct {
+	Statements []StatementNode
+}
+
+func (p *Program) TokenLiteral() string {
+	if len(p.Statements) > 0 {
+		return p.Statements[0].TokenLiteral()
+	} else {
+		return ""
+	}
+}
+
+func (p *Program) String() string {
+	out := strings.Builder{}
+
+	for _, statement := range p.Statements {
+		out.WriteString(statement.String(0))
+		out.WriteString("\n")
+	}
+
+	return out.String()
+}
+
 type Block struct {
 	Token      token.Token // the RBrace token
 	Statements []StatementNode
@@ -66,7 +89,7 @@ type Function struct {
 	Arguments     []FunctionArgument
 	ReturnType    Type
 	HasReturnType bool
-	Block         Block
+	Block         *Block
 }
 
 func (f *Function) TokenLiteral() string { return f.Token.Literal }

lexer/lexer.go

@@ -48,7 +48,7 @@ func (l *Lexer) readChar() {
 }
 
 func (l *Lexer) makeToken(t token.TokenType, literal string) token.Token {
-	return token.Token{Token: t, Literal: literal, Loc: token.Loc{Line: l.line, Col: l.col}}
+	return token.Token{Type: t, Literal: literal, Loc: token.Loc{Line: l.line, Col: l.col}}
 }
 
 func isDigit(ch byte) bool {
@@ -81,7 +81,7 @@ func (l *Lexer) readIdentifier() token.Token {
 
 	t := token.LookupKeyword(l.input[pos:l.pos])
 
-	return token.Token{Token: t, Loc: loc, Literal: l.input[pos:l.pos]}
+	return token.Token{Type: t, Loc: loc, Literal: l.input[pos:l.pos]}
 }
 
 func (l *Lexer) readNumber() token.Token {
@@ -92,7 +92,7 @@ func (l *Lexer) readNumber() token.Token {
 		l.readChar()
 	}
 
-	return token.Token{Token: token.Integer, Loc: loc, Literal: l.input[pos:l.pos]}
+	return token.Token{Type: token.Integer, Loc: loc, Literal: l.input[pos:l.pos]}
 }
 
 func (l *Lexer) NextToken() token.Token {
@@ -103,21 +103,23 @@ func (l *Lexer) NextToken() token.Token {
 
 	switch l.ch {
 	case '\n':
-		tok.Token = token.NewLine
+		tok.Type = token.NewLine
 	case ';':
-		tok.Token = token.Semicolon
+		tok.Type = token.Semicolon
 	case ':':
-		tok.Token = token.Colon
+		tok.Type = token.Colon
+	case ',':
+		tok.Type = token.Comma
 	case '=':
-		tok.Token = token.Equal
+		tok.Type = token.Equal
 	case '{':
-		tok.Token = token.LBrace
+		tok.Type = token.LBrace
 	case '}':
-		tok.Token = token.RBrace
+		tok.Type = token.RBrace
 	case '(':
-		tok.Token = token.LParen
+		tok.Type = token.LParen
 	case ')':
-		tok.Token = token.RParen
+		tok.Type = token.RParen
 
 	case 0:
 		return l.makeToken(token.Eof, "")
@@ -129,7 +131,7 @@ func (l *Lexer) NextToken() token.Token {
 			return l.readNumber()
 		}
 
-		tok.Token = token.Illegal
+		tok.Type = token.Illegal
 	}
 
 	l.readChar()

lexer/lexer_test.go

@@ -12,19 +12,19 @@ func TestCorrectTokens(t *testing.T) {
 		expectedTokens []token.Token
 		input          string
 	}{{
-		expectedTokens: []token.Token{{Token: token.Eof, Literal: "", Loc: token.Loc{Line: 1, Col: 1}}},
+		expectedTokens: []token.Token{{Type: token.Eof, Literal: "", Loc: token.Loc{Line: 1, Col: 1}}},
 		input:          "",
 	}, {input: "hello 1234 ; () {}\n",
 		expectedTokens: []token.Token{
-			{Token: token.Identifier, Literal: "hello", Loc: token.Loc{Line: 1, Col: 1}},
-			{Token: token.Integer, Literal: "1234", Loc: token.Loc{Line: 1, Col: 7}},
-			{Token: token.Semicolon, Literal: ";", Loc: token.Loc{Line: 1, Col: 12}},
-			{Token: token.LParen, Literal: "(", Loc: token.Loc{Line: 1, Col: 14}},
-			{Token: token.RParen, Literal: ")", Loc: token.Loc{Line: 1, Col: 15}},
-			{Token: token.LBrace, Literal: "{", Loc: token.Loc{Line: 1, Col: 17}},
-			{Token: token.RBrace, Literal: "}", Loc: token.Loc{Line: 1, Col: 18}},
-			{Token: token.NewLine, Literal: "\n", Loc: token.Loc{Line: 2, Col: 1}},
-			{Token: token.Eof, Literal: "", Loc: token.Loc{Line: 2, Col: 2}},
+			{Type: token.Identifier, Literal: "hello", Loc: token.Loc{Line: 1, Col: 1}},
+			{Type: token.Integer, Literal: "1234", Loc: token.Loc{Line: 1, Col: 7}},
+			{Type: token.Semicolon, Literal: ";", Loc: token.Loc{Line: 1, Col: 12}},
+			{Type: token.LParen, Literal: "(", Loc: token.Loc{Line: 1, Col: 14}},
+			{Type: token.RParen, Literal: ")", Loc: token.Loc{Line: 1, Col: 15}},
+			{Type: token.LBrace, Literal: "{", Loc: token.Loc{Line: 1, Col: 17}},
+			{Type: token.RBrace, Literal: "}", Loc: token.Loc{Line: 1, Col: 18}},
+			{Type: token.NewLine, Literal: "\n", Loc: token.Loc{Line: 2, Col: 1}},
+			{Type: token.Eof, Literal: "", Loc: token.Loc{Line: 2, Col: 2}},
 		}}}
 
 	for _, test := range tests {
@@ -36,8 +36,8 @@ func TestCorrectTokens(t *testing.T) {
 				t.Errorf("Literal is not equal: actual = (%v) is not expected = (%v)", actual.Literal, expected.Literal)
 			}
 
-			if expected.Token != actual.Token {
-				t.Errorf("Token is not equal: actual = (%v) is not expected = (%v)", actual.Token, expected.Token)
+			if expected.Type != actual.Type {
+				t.Errorf("Token is not equal: actual = (%v) is not expected = (%v)", actual.Type, expected.Type)
 			}
 
 			if expected.Loc.Line != actual.Loc.Line {

parser/parser.go

@@ -1 +1,163 @@
 package parser
+
+import (
+	"fmt"
+
+	"git.robaertschi.xyz/robaertschi/thorgot/ast"
+	"git.robaertschi.xyz/robaertschi/thorgot/lexer"
+	"git.robaertschi.xyz/robaertschi/thorgot/token"
+)
+
+type Parser struct {
+	lexer     lexer.Lexer
+	curToken  token.Token
+	peekToken token.Token
+
+	Errors []error
+}
+
+func New(lexer lexer.Lexer) Parser {
+	p := Parser{}
+
+	p.nextToken()
+	p.nextToken()
+
+	return p
+}
+
+func (p *Parser) error(err error) ast.StatementNode {
+	p.Errors = append(p.Errors, err)
+	return nil
+}
+
+func (p *Parser) expectPeek(t token.TokenType) bool {
+	if p.peekToken.Type == t {
+		p.nextToken()
+		return true
+	} else {
+		p.peekError(t)
+		return false
+	}
+}
+
+func (p *Parser) peekTokenIs(t token.TokenType) bool {
+	return p.peekToken.Type == t
+}
+
+func (p *Parser) peekError(t token.TokenType) {
+	err := fmt.Errorf("Expected token %v to be %v", t, p.peekToken.Type)
+	p.Errors = append(p.Errors, err)
+}
+
+func (p *Parser) nextToken() {
+	p.curToken = p.peekToken
+	p.peekToken = p.lexer.NextToken()
+}
+
+func (p *Parser) ParseProgram() ast.Program {
+	program := ast.Program{}
+	program.Statements = make([]ast.StatementNode, 0)
+
+	for p.curToken.Type != token.Eof {
+		stmt := p.parseStatement()
+		if stmt != nil {
+			program.Statements = append(program.Statements, stmt)
+		}
+	}
+
+	return program
+}
+
+func (p *Parser) parseStatement() ast.StatementNode {
+	switch p.curToken.Type {
+	case token.Fn:
+		return p.parseFunction()
+	}
+
+	return p.error(fmt.Errorf("Invalid token %v found with literal %v", p.curToken.Type, p.curToken.Literal))
+}
+
+func (p *Parser) parseFunctionArguments() []ast.FunctionArgument {
+	args := make([]ast.FunctionArgument, 0)
+
+	for p.peekTokenIs(token.Identifier) {
+		p.nextToken()
+		name := p.curToken.Literal
+
+		if !p.expectPeek(token.Identifier) {
+			return nil
+		}
+
+		args = append(args, ast.FunctionArgument{Name: name, Type: ast.Type(p.curToken.Literal)})
+
+		if !p.peekTokenIs(token.Comma) {
+			break
+		}
+		p.nextToken()
+	}
+
+	if !p.expectPeek(token.RParen) {
+		return nil
+	}
+
+	return args
+}
+
+func (p *Parser) parseFunction() *ast.Function {
+	f := &ast.Function{Token: p.curToken}
+
+	if !p.expectPeek(token.Identifier) {
+		return nil
+	}
+
+	f.Name = p.curToken.Literal
+
+	if !p.expectPeek(token.LParen) {
+		return nil
+	}
+
+	args := p.parseFunctionArguments()
+
+	if args == nil {
+		return nil
+	}
+
+	f.Arguments = args
+
+	if p.peekTokenIs(token.Identifier) {
+		p.nextToken()
+		f.ReturnType = ast.Type(p.curToken.Literal)
+		f.HasReturnType = true
+	}
+
+	if !p.expectPeek(token.LBrace) {
+		return nil
+	}
+
+	// parse block
+
+	f.Block = p.parseBlock()
+	if f.Block == nil {
+		return nil
+	}
+
+	return f
+}
+
+func (p *Parser) parseBlock() *ast.Block {
+	b := &ast.Block{Token: p.curToken}
+	// skip {
+	p.nextToken()
+
+	for p.curToken.Type != token.RBrace {
+		stmt := p.parseStatement()
+		if stmt == nil {
+			return nil
+		}
+		b.Statements = append(b.Statements, stmt)
+	}
+
+	p.nextToken()
+
+	return b
+}

token/token.go

@@ -8,7 +8,7 @@ type Loc struct {
 }
 
 type Token struct {
-	Token   TokenType
+	Type    TokenType
 	Literal string
 	Loc     Loc
 }
@@ -21,6 +21,7 @@ const (
 
 	Semicolon = "Semicolon" // ;
 	Colon     = "Colon"     // :
+	Comma     = ","         // ,
 	Equal     = "Equal"     // =
 	LBrace    = "LBrace"    // {
 	RBrace    = "RBrace"    // }