first tests for recursion

test/src/ll1/no-recursion.js

@@ -0,0 +1,96 @@
+import test from 'ava' ;
+
+import { iter , map , enumerate , list , range , nrepeat , ncycle } from '@aureooms/js-itertools' ;
+import * as stream from '@aureooms/js-stream' ;
+import { grammar , ast , ll1 } from '../../../src' ;
+
+function flatten ( t , n ) {
+
+	const G = grammar.from( {
+		"start" : "letters" ,
+		"eof" : "$" ,
+		"productions" : {
+			"letters" : {
+				"add" : [ "&letter" , "&letters" ] ,
+				"end" : [ ] ,
+			} ,
+			"letter" : {
+				"x" : [ "=x" ] ,
+			} ,
+		} ,
+	} ) ;
+
+	t.true(ll1.is(G));
+
+	const parser = ll1.from(G);
+
+	const tokens = stream.fromiterable(
+		map(
+			i => ({
+				"type" : "leaf" ,
+				"terminal" : "x" ,
+				"buffer" : "x" ,
+				"position" : i ,
+			}) ,
+			range(n)
+		)
+	) ;
+
+	const tree = parser.parse(tokens);
+
+	t.is( list( map( leaf => leaf.buffer , ast.flatten( tree ) ) ).join('') , list(nrepeat('x', n)).join('') ) ;
+
+}
+
+flatten.title = ( _ , n ) => `Tail-recursion: flatten repetition of a single letter x${n} times.` ;
+
+test( flatten , 1000 ) ;
+test( flatten , 10000 ) ;
+test( flatten , 100000 ) ;
+
+
+function materialize ( t , n ) {
+
+	const G = grammar.from( {
+		"start" : "letters" ,
+		"eof" : "$" ,
+		"productions" : {
+			"letters" : {
+				"add" : [ "&letter" , "&letters" ] ,
+				"end" : [ ] ,
+			} ,
+			"letter" : {
+				"x" : [ "=x" ] ,
+			} ,
+		} ,
+	} ) ;
+
+	t.true(ll1.is(G));
+
+	const parser = ll1.from(G);
+
+	const tokens = stream.fromiterable(
+		map(
+			i => ({
+				"type" : "leaf" ,
+				"terminal" : "x" ,
+				"buffer" : "x" ,
+				"position" : i ,
+			}) ,
+			range(n)
+		)
+	) ;
+
+	const tree = parser.parse(tokens);
+
+	const materialized = ast.materialize(tree) ;
+
+	t.is( list( map( leaf => leaf.buffer , ast.flatten( materialized ) ) ).join('') , list(nrepeat('x', n)).join('') ) ;
+
+}
+
+materialize.title = ( _ , n ) => `Tail-recursion: materialize repetition of a single letter x${n} times.` ;
+
+test( materialize , 1000 ) ;
+test( materialize , 10000 ) ;
+test( materialize , 100000 ) ;