fix the bug of calc DR set

LALR/LALR.go

@@ -162,7 +162,7 @@ func (lalr *LALR1) CalcDR() {
 	//set the start -> S' Dr is $ sym
 	// 0 index transistor is I0--S'-->
 	// 1 is dollor symbol
-	lalr.DRSet[0] = []int{1}
+	lalr.DRSet[0] = append(lalr.DRSet[0], []int{1}...)
 }
 
 //-----------------Caculate the Includes relation-------------
@@ -262,8 +262,14 @@ func ComputeLALR(g *grammar.Grammar) *LALR1 {
 		for k := range lalr.trans {
 			fmt.Println(lalr.showTrans(k))
 		}
-		fmt.Println("==========LOOKAHEAD SET===============")
+		fmt.Println("==========Show Direct Read SET===============")
+		lalr.ShowDrSet()
+		fmt.Println("==========Show Reads SET===============")
+		lalr.ShowReadSet()
+		fmt.Println("==========Show FollowSet SET===============")
 		lalr.ShowFollowSet()
+		fmt.Println("==========Show LookAhead SET===============")
+		lalr.ShowLookAheadSet()
 	}
 
 	if tab, err := lalr.GenTable(); err != nil {

LALR/Utils.go

@@ -41,15 +41,25 @@ func (lalr *LALR1) ShowDrSet() {
 	for trIndex, set := range lalr.DRSet {
 		q := lalr.trans[trIndex].q
 		symName := lalr.fetchSymbol(int(lalr.trans[trIndex].sym_or_rule)).Name
-		fmt.Printf("%d--%s--> %v\n", q, symName, set)
+		var str_set string = "["
+		for _, v := range set {
+			str_set += lalr.fetchSymbol(v).Name + " "
+		}
+		str_set += " ]"
+		fmt.Printf("%d--%s--> %s\n", q, symName, str_set)
 	}
 }
 
 func (lalr *LALR1) ShowReadSet() {
 	for trIndex, set := range lalr.ReadSet {
 		q := lalr.trans[trIndex].q
 		symName := lalr.fetchSymbol(int(lalr.trans[trIndex].sym_or_rule)).Name
-		fmt.Printf("%d--%s--> %v\n", q, symName, set)
+		var str_set string = "["
+		for _, v := range set {
+			str_set += lalr.fetchSymbol(v).Name + " "
+		}
+		str_set += " ]"
+		fmt.Printf("%d--%s--> %s\n", q, symName, str_set)
 	}
 }
 

examples/ladd.y

@@ -0,0 +1,74 @@
+// language: go
+
+	%{
+
+	package main
+
+	import (
+
+		"fmt"
+
+	)
+
+	%}
+
+	%union {
+		val int
+	}
+
+	%type	<val>	E
+	%token  PLUS NL
+	%token	<val>	NUM
+	%token NUM 100
+	%start PROG
+    %left PLUS
+%%
+PROG:
+    /*empty*/
+    | PROG E NL
+E:
+	E PLUS E {
+		$$	=	$1 + $3
+	}	
+	| NUM {
+		$$	=	$1
+	}
+
+%%
+	const EOF = -1
+	// The parser expects the lexer to return 0 on EOF.  Give it a name
+	// for clarity.
+	func GetToken(input string, valTy *ValType, pos *int) int {
+		if *pos >= len(input) {
+			return -1
+		} else {
+			*valTy = ValType{0}
+		loop:
+			if *pos >= len(input) {
+				return EOF
+			}
+			c := input[*pos]
+			*pos++
+			switch c {
+			case '+':
+                return PLUS	
+            case '\n':
+                return NL
+			default:
+				if c >= '0' && c <= '9' { // is digit
+					valTy.val = (valTy.val)*10 + int(c) - '0'
+					// next is digit
+					if *pos < len(input) && input[*pos] >= '0' && input[*pos] <= '9' {
+						goto loop
+					}
+					return NUM
+				}
+
+			}
+			return 0
+		}
+	}
+func main() {
+	v := Parser("1+2\n").val
+	fmt.Println(v)
+}