func parseDefine(node *ast.Tuple) ast.Node {
fmt.Println("#parseDefine")
nNode := len(node.Nodes)
if nNode != 3 {
panic("unexpeced define expression")
}
// implicit lambda expressions, e.g., (define (add x y) (+ x y))
var vars ast.Node
var expr ast.Node
if node.Nodes[1].Type() == const_.TUPLE {
t := node.Nodes[1].(*ast.Tuple)
vars = t.Nodes[0]
var args []ast.Node
for _, node := range t.Nodes[1:] {
args = append(args, node)
}
body := parseNode(node.Nodes[2])
expr = ast.NewLambda(ast.NewTuple(args), body)
} else {
// 1. normal definition, e.g. (defien a 1)
// 2. explicit lambda expressions, e.g. (define inc (lambda (x) (+ x 1)))
vars = node.Nodes[1]
expr = parseNode(node.Nodes[2])
}
return ast.NewDefine(vars, expr)
}
func (self *Parser) parse(nodes *[]ast.Node, dep int, typ lexer.TokenType) {
for token := self.l.NextToken(); token.Type != lexer.TokenEOF; token = self.l.NextToken() {
//fmt.Println(token.Name)
var node ast.Node
switch token.Type {
case lexer.TokenBool:
node = ast.NewBool(token.Name)
case lexer.TokenChar:
node = ast.NewChar(token.Name)
case lexer.TokenString:
node = ast.NewString(token.Name)
case lexer.TokenQuote:
quoteExpr := []ast.Node{ast.NewIdent(const_.QUOTE)}
self.parse("eExpr, dep+1, lexer.TokenQuote)
node = ast.NewTuple(quoteExpr)
case lexer.TokenQuasiQuote:
qqExpr := []ast.Node{ast.NewIdent(const_.QUASIQUOTE)}
self.parse(&qqExpr, dep+1, lexer.TokenQuasiQuote)
node = ast.NewTuple(qqExpr)
case lexer.TokenUnQuote:
expr := []ast.Node{ast.NewIdent(const_.UNQUOTE)}
self.parse(&expr, dep+1, lexer.TokenUnQuote)
node = ast.NewTuple(expr)
case lexer.TokenUnQuoteSplicing:
expr := []ast.Node{ast.NewIdent(const_.UNQUOTE_SPLICING)}
self.parse(&expr, dep+1, lexer.TokenUnQuoteSplicing)
node = ast.NewTuple(expr)
case lexer.TokenIdent:
node = ast.NewIdent(token.Name)
case lexer.TokenNumber:
if strings.ContainsAny(token.Name, "Ee.") {
node = ast.NewFloat(token.Name)
} else {
node = ast.NewInt(token.Name)
}
case lexer.TokenLParen:
sub := make([]ast.Node, 0)
self.parse(&sub, dep+1, -1)
node = ast.NewTuple(sub)
case lexer.TokenRParen:
return
case lexer.TokenLVect:
vect := []ast.Node{ast.NewIdent(const_.VECT)}
self.parse(&vect, dep+1, -1)
node = ast.NewTuple(vect)
case lexer.TokenRVect:
return
default:
panic("unexpected token")
}
*nodes = append(*nodes, node)
if (typ == lexer.TokenQuote || typ == lexer.TokenQuasiQuote) ||
(typ == lexer.TokenUnQuote || typ == lexer.TokenUnQuoteSplicing) {
break
}
}
}