From d4303f0d8e9b485ec54a59aa54c8bd353f10b70e Mon Sep 17 00:00:00 2001
From: maestrow <andrew.shmelev@gmail.com>
Date: Sun, 23 May 2021 17:15:44 +0300
Subject: [PATCH] 1st LR working example

---
 src/cli.ts    | 39 ++++++++++++++++++++++-----------------
 src/parser.ts | 30 +++++++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 18 deletions(-)

diff --git a/src/cli.ts b/src/cli.ts
index 5557936..4761f69 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -1,11 +1,9 @@
 import * as fs from "fs";
 import { IMatchResult, Parser } from './parser'
-import { Ast } from './grammar-ast'
-import { math1 } from './grammars/math1'
-import { ometa1, proj } from './grammars/ometa1'
 import { TraceDiscovery } from "./utils/trace-discover";
 import { IParserFn } from "types";
 import * as equal from "fast-deep-equal/es6";
+import { Ast } from "grammar-ast";
 
 const printTrace = (p: Parser, input) => {
   const disco = new TraceDiscovery(p.grammar, input, p.trace.data)
@@ -26,20 +24,27 @@ const printRes = (p: Parser, res: IMatchResult) => {
   // console.dir(trace, {depth:1})
 }
 
-const input = fs.readFileSync('src/grammars/ometa1.ometa', 'utf-8')
-const p = new Parser(ometa1, proj)
-const r = p.match(input as unknown as any[], 'ometa')
-
-saveTrace(p, input)
+type Expr = 
+  | ['lr', Ast.Expr]
+type Grammar = Ast.Grammar<Expr>
+
+const g: Grammar = [
+  ['expr', ['lr', ['alt', [
+    ['seq', [
+      ['rule', 'expr'],
+      ['equal', '+'],
+      ['rule', 'num'],
+    ]],
+    ['rule', 'num']
+  ]]]],
+  ['num', ['range', '0', '9']]
+]
+
+const input = "1+2+3"
+const p = new Parser(g)
+const r = p.match(input as unknown as any[], 'expr')
+
+// saveTrace(p, input)
 printRes(p, r)
-const isEqual = equal(ometa1, r.result)
-
-console.log('\nDiff:\n')
-console.log('isEqual: ' + isEqual)
-
-fs.writeFileSync("./dist/diff_expected.json", JSON.stringify(ometa1, null, 2))
-fs.writeFileSync("./dist/diff_actual.json", JSON.stringify(r.result, null, 2))
-
-
 
 
diff --git a/src/parser.ts b/src/parser.ts
index b664f05..8da2a62 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -15,6 +15,8 @@ export interface IMatchResult {
   result?: any
 }
 
+let counter = 0
+let memo: IParseResult
 export class Parser implements Ast.IParser {
 
   protected state: State
@@ -64,7 +66,7 @@ export class Parser implements Ast.IParser {
   // ToDo: translate Если ф-ция парсера вызывает другую ф-цию парсера, то успешный результат вложенного парсера нельзя пробрасывать наверх. 
   // Иначе может произойти двойной консум
 
-  @Memoize((...args) => JSON.stringify(args))
+  //@Memoize((...args) => JSON.stringify(args))
   expr (e: Ast.GenericExpr): IParserFn {
     const combinator = this[e[0]]
     if (typeof(combinator) !== 'function') {
@@ -91,6 +93,32 @@ export class Parser implements Ast.IParser {
     return () => this.project(name, e)()
   }
 
+  lr = (expr: Ast.GenericExpr) => {
+    const p = this.expr(expr)
+
+    return () => {
+      console.log(counter, memo)
+      if (counter === 0) {
+        counter++
+        let res = p()
+        memo = res
+        console.log(memo)
+        while (res.success) {
+          res = p()
+          if (res.success)
+            memo = res
+        }
+        return memo
+      } else if (counter === 1) {
+        counter++
+        return this.fail()
+      } else {
+        counter++
+        return memo
+      }
+    }
+  }
+
   empty = (): IParserFn => () => {
     return this.success()
   }