do not fail on tokens that cannot be identified by scope

Author: chrisdickinson

lib/expr.js

@@ -81,9 +81,10 @@ prefix('!')
 prefix('~')
 prefix('defined')
 prefix('(', function() {
-  var v = expression(0)
+  this.type = 'group'
+  this.children = [expression(0)]
   advance(')')
-  return v
+  return this 
 })
 prefix('++')
 prefix('--')
@@ -148,6 +149,7 @@ function symbol(id, binding_power) {
 function expression(rbp) {
   var left, t = token
   advance()
+
   left = t.nud()
   while(rbp < token.lbp) {
     t = token
@@ -224,7 +226,7 @@ function advance(id) {
   type = next.type
 
   if(type === 'ident') {
-    output = state.scope.find(value)
+    output = state.scope.find(value) || state.create_node()
   } else if(type === 'builtin') {
     output = symbol_table['(builtin)']
   } else if(type === 'keyword') {

lib/index.js

@@ -17,6 +17,7 @@ var Advance = new Object
 var DEBUG = false
 
 var _ = 0
+  , IDENT = _++
   , STMT = _++
   , STMTLIST = _++
   , STRUCT = _++
@@ -33,7 +34,6 @@ var _ = 0
   , PREPROCESSOR = _++
   , KEYWORD = _++
   , KEYWORD_OR_IDENT = _++
-  , IDENT = _++
   , RETURN = _++
   , BREAK = _++
   , CONTINUE = _++
@@ -54,7 +54,8 @@ var token_map = {
 
 // map of stmt types to human
 var stmt_type = _ = [ 
-    'stmt'
+    'ident'
+  , 'stmt'
   , 'stmtlist'
   , 'struct'
   , 'function'
@@ -70,7 +71,6 @@ var stmt_type = _ = [
   , 'preprocessor'
   , 'keyword'
   , 'keyword_or_ident'
-  , 'ident'
   , 'return'
   , 'break'
   , 'continue'
@@ -127,6 +127,11 @@ function parser() {
   state.fake = special_fake
   state.unexpected = unexpected
   state.scope = new Scope(state)
+  state.create_node = function() {
+    var n = mknode(IDENT, token)
+    n.parent = stream.program
+    return n
+  }
 
   // setup root node
   node = stmtlist()
@@ -309,9 +314,9 @@ function parser() {
           case 'if': return state.unshift(ifstmt());
           case 'while': return state.unshift(whilestmt());
           case 'do': return state.unshift(dowhilestmt());
-          case 'break': return state.fake(mknode(BREAK, token, node)), tokens.shift()
-          case 'continue': return state.fake(mknode(CONTINUE, token, node)), tokens.shift()
-          case 'discard': return state.fake(mknode(DISCARD, token, node)), tokens.shift()
+          case 'break': return state.fake(mknode(BREAK, token)), tokens.shift()
+          case 'continue': return state.fake(mknode(CONTINUE, token)), tokens.shift()
+          case 'discard': return state.fake(mknode(DISCARD, token)), tokens.shift()
           case 'return': return state.unshift(returnstmt());
         }
         if(token.data === 'struct')
@@ -516,7 +521,7 @@ function parser() {
   function n(type) {
     // this is a function factory that suffices for most kinds of expressions and statements
     return function() {
-      return mknode(type, token, node)
+      return mknode(type, token)
     }
   }
 
@@ -688,7 +693,7 @@ function parser() {
             var lookup
             if(token.type === 'ident') {
               if(!(lookup = state.scope.find(token.data))) {
-                return
+                lookup = state.create_node()
               }
 
               if(lookup.parent.type === 'struct') {
@@ -798,11 +803,10 @@ function parser() {
   }
 }
 
-function mknode(mode, sourcetoken, parent) {
+function mknode(mode, sourcetoken) {
   return {
       mode: mode
     , token: sourcetoken
-    , parent: parent
     , children: []
     , type: stmt_type[mode]
     , id: (Math.random() * 0xFFFFFFFF).toString(16)

lib/scope.js

@@ -33,7 +33,6 @@ proto.find = function(name, fail) {
       return this.scopes[i][name]
     }
   }
-  return (fail === undefined || fail) ? this.state.unexpected(
-    'attempted to lookup undefined symbol '+name
-  ) : null
+
+  return null
 }