parser (still doesn't work)

parser/ast.go

@@ -4,32 +4,62 @@ import (
 	"fmt"
 )
 
+type RuleKind int
+
+const (
+	RK_Required RuleKind = iota
+	RK_Optional
+	RK_Repeat
+	RK_Port
+)
+
 type Rule struct {
 	Name  string
+	Kind  RuleKind
 	Inner []Rule
 }
 
 type AstNode struct {
 	Rule  Rule
+	Value string
 	Inner []AstNode
 }
 
 func (t AstNode) String() string {
-	return fmt.Sprintf("AstNode(\n  rule=%v,\n  inner=%v,\n)", t.Rule, t.Inner)
+	return fmt.Sprintf("AstNode(\n  value=%s\n  rule=%v,\n  inner=%v,\n)", t.Value, t.Rule, t.Inner)
 }
 func (t Rule) String() string {
 	return t.Name
 }
 
 func NewRule(name string, inner []Rule) Rule {
-	return Rule{name, inner}
+	return Rule{name, RK_Required, inner}
+}
+
+func NewPort(name string, inner []Rule) Rule {
+	return Rule{name, RK_Port, inner}
+}
+
+func Optional(rule Rule) Rule {
+	rule.Kind = RK_Optional
+	return rule
+}
+
+func Repeat(rule Rule) Rule {
+	rule.Kind = RK_Repeat
+	return rule
 }
 
 var (
-	IDENTIFIER = NewRule("IDENTIFIER", []Rule{})
+	IDENTIFIER = NewPort("IDENTIFIER", []Rule{})
+	NUMBER     = NewPort("NUMBER", []Rule{})
+	SEMICOLON  = NewPort("SEMICOLON", []Rule{})
+	EXPR       = NewRule("EXPR", []Rule{IDENTIFIER})
+	CODE_BLOCK = NewRule("CODE_BLOCK", []Rule{EXPR, SEMICOLON})
 	VAR_DEF    = NewRule("VAR_DEF", []Rule{IDENTIFIER, IDENTIFIER})
+	FUNC_DEF   = NewRule("FUNC_DEF", []Rule{IDENTIFIER, IDENTIFIER, CODE_BLOCK})
 )
 
 var (
-	RULE_SET = []Rule{IDENTIFIER, VAR_DEF}
+	TOP_RULE = []Rule{FUNC_DEF}
 )