perf: introduce AST to avoid reparse

src/util/assert.ts

@@ -1,8 +1,8 @@
 import { AssertionError } from './error'
 
-export function assert <T> (predicate: T | null | undefined, message?: string) {
+export function assert <T> (predicate: T | null | undefined, message?: () => string) {
   if (!predicate) {
-    message = message || `expect ${predicate} to be true`
-    throw new AssertionError(message)
+    const msg = message ? message() : `expect ${predicate} to be true`
+    throw new AssertionError(msg)
   }
 }

src/util/async.ts

@@ -1,6 +1,6 @@
 import { isFunction } from './underscore'
 
-type resolver = (x?: any) => Thenable
+type resolver = (x?: any) => any
 
 interface Thenable {
   then (resolve: resolver, reject?: resolver): Thenable;

src/util/character.ts

@@ -0,0 +1,10 @@
+// bitmask character types to boost performance
+// generated by bin/char-types.js
+export const TYPES = [0, 0, 0, 0, 0, 0, 0, 0, 0, 20, 4, 0, 0, 20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 20, 2, 8, 0, 0, 0, 0, 8, 0, 0, 0, 64, 0, 65, 0, 0, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 0, 0, 2, 2, 2, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0]
+export const VARIABLE = 1
+export const OPERATOR = 2
+export const BLANK = 4
+export const QUOTE = 8
+export const INLINE_BLANK = 16
+export const NUMBER = 32
+export const SIGN = 64

src/util/error.ts

@@ -1,5 +1,5 @@
 import * as _ from './underscore'
-import { Token } from '../parser/token'
+import { Token } from '../tokens/token'
 import { Template } from '../template/template'
 
 abstract class LiquidError extends Error {
@@ -57,14 +57,15 @@ export class AssertionError extends Error {
 }
 
 function mkContext (token: Token) {
+  const [line] = token.getPosition()
   const lines = token.input.split('\n')
-  const begin = Math.max(token.line - 2, 1)
-  const end = Math.min(token.line + 3, lines.length)
+  const begin = Math.max(line - 2, 1)
+  const end = Math.min(line + 3, lines.length)
 
   const context = _
     .range(begin, end + 1)
     .map(lineNumber => {
-      const indicator = (lineNumber === token.line) ? '>> ' : '   '
+      const indicator = (lineNumber === line) ? '>> ' : '   '
       const num = _.padStart(String(lineNumber), String(end).length)
       const text = lines[lineNumber - 1]
       return `${indicator}${num}| ${text}`
@@ -76,6 +77,7 @@ function mkContext (token: Token) {
 
 function mkMessage (msg: string, token: Token) {
   if (token.file) msg += `, file:${token.file}`
-  msg += `, line:${token.line}, col:${token.col}`
+  const [line, col] = token.getPosition()
+  msg += `, line:${line}, col:${col}`
   return msg
 }

src/util/literal.ts

@@ -0,0 +1,12 @@
+import { NullDrop } from '../drop/null-drop'
+import { EmptyDrop } from '../drop/empty-drop'
+import { BlankDrop } from '../drop/blank-drop'
+
+export const literalValues = {
+  'true': true,
+  'false': false,
+  'nil': new NullDrop(),
+  'null': new NullDrop(),
+  'empty': new EmptyDrop(),
+  'blank': new BlankDrop()
+}

src/util/type-guards.ts

@@ -0,0 +1,55 @@
+import { OperatorToken } from '../tokens/operator-token'
+import { WordToken } from '../tokens/word-token'
+import { TagToken } from '../tokens/tag-token'
+import { HTMLToken } from '../tokens/html-token'
+import { OutputToken } from '../tokens/output-token'
+import { PropertyAccessToken } from '../tokens/property-access-token'
+import { LiteralToken } from '../tokens/literal-token'
+import { QuotedToken } from '../tokens/quoted-token'
+import { NumberToken } from '../tokens/number-token'
+import { RangeToken } from '../tokens/range-token'
+import { TokenKind } from '../parser/token-kind'
+
+export function isOperatorToken (val: any): val is OperatorToken {
+  return getKind(val) === TokenKind.Operator
+}
+
+export function isHTMLToken (val: any): val is HTMLToken {
+  return getKind(val) === TokenKind.HTML
+}
+
+export function isOutputToken (val: any): val is OutputToken {
+  return getKind(val) === TokenKind.Output
+}
+
+export function isTagToken (val: any): val is TagToken {
+  return getKind(val) === TokenKind.Tag
+}
+
+export function isQuotedToken (val: any): val is QuotedToken {
+  return getKind(val) === TokenKind.Quoted
+}
+
+export function isLiteralToken (val: any): val is LiteralToken {
+  return getKind(val) === TokenKind.Literal
+}
+
+export function isNumberToken (val: any): val is NumberToken {
+  return getKind(val) === TokenKind.Number
+}
+
+export function isPropertyAccessToken (val: any): val is PropertyAccessToken {
+  return getKind(val) === TokenKind.PropertyAccess
+}
+
+export function isWordToken (val: any): val is WordToken {
+  return getKind(val) === TokenKind.Word
+}
+
+export function isRangeToken (val: any): val is RangeToken {
+  return getKind(val) === TokenKind.Range
+}
+
+function getKind (val: any) {
+  return val ? val.kind : -1
+}