From 07cc8c1c6fa803777fa669301b132b7ee121a06d Mon Sep 17 00:00:00 2001
From: Steve Larson <9larsons@gmail.com>
Date: Thu, 17 Oct 2024 10:05:50 -0500
Subject: [PATCH] Added support for single character strings (#91)

ref https://github.com/TryGhost/NQL/issues/20

I -believe- this works all right. It's at the end of the rules so it should allow for matching on just about anything else practical, then allow us a chance at matching a single character string, before throwing a Lexical Error.

I've added negation for all special chars except for + and - as you ought to be able to do 'post:a+other' and 'post:a-something'.
---
 packages/nql-lang/dist/parser.js      |  6 ++++--
 packages/nql-lang/src/nql.l           |  1 +
 packages/nql-lang/test/lexer.test.js  | 14 +++++++++++---
 packages/nql-lang/test/parser.test.js |  6 ++++++
 4 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/packages/nql-lang/dist/parser.js b/packages/nql-lang/dist/parser.js
index 3608b05a..6ab01a7f 100644
--- a/packages/nql-lang/dist/parser.js
+++ b/packages/nql-lang/dist/parser.js
@@ -743,10 +743,12 @@ case 25:return 35;
 break;
 case 26:return 33;
 break;
+case 27:return 29;
+break;
 }
 },
-rules: [/^(?:\s+)/,/^(?:(?:null|NULL|Null)(?!(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+))/,/^(?:(?:true|TRUE|True)(?!(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+))/,/^(?:(?:false|FALSE|False)(?!(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+))/,/^(?:[a-zA-Z_][a-zA-Z0-9_\.]*[:])/,/^(?:[0-9]+(\.[0-9]+)?\b(?![\-]))/,/^(?:\[)/,/^(?:\])/,/^(?:now(?=[-+]\d+[dwMyhms](?:([\+\,\(\)\[\]])|$)))/,/^(?:-)/,/^(?:\+)/,/^(?:\d+)/,/^(?:[dwMyhms])/,/^(?:([^\s'"\+\,\(\)\>\<=\[\]\~\-])(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+)/,/^(?:['](\\['"]|[^'"])+?['])/,/^(?:\()/,/^(?:\))/,/^(?:,)/,/^(?:\+)/,/^(?:-)/,/^(?:>=)/,/^(?:<=)/,/^(?:>)/,/^(?:<)/,/^(?:~\^)/,/^(?:~\$)/,/^(?:~)/],
-conditions: {"reldate":{"rules":[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26],"inclusive":true},"INITIAL":{"rules":[0,1,2,3,4,5,6,7,8,13,14,15,16,17,18,19,20,21,22,23,24,25,26],"inclusive":true}}
+rules: [/^(?:\s+)/,/^(?:(?:null|NULL|Null)(?!(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+))/,/^(?:(?:true|TRUE|True)(?!(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+))/,/^(?:(?:false|FALSE|False)(?!(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+))/,/^(?:[a-zA-Z_][a-zA-Z0-9_\.]*[:])/,/^(?:[0-9]+(\.[0-9]+)?\b(?![\-]))/,/^(?:\[)/,/^(?:\])/,/^(?:now(?=[-+]\d+[dwMyhms](?:([\+\,\(\)\[\]])|$)))/,/^(?:-)/,/^(?:\+)/,/^(?:\d+)/,/^(?:[dwMyhms])/,/^(?:([^\s'"\+\,\(\)\>\<=\[\]\~\-])(\\(['"\+\,\(\)\>\<=\[\]\~\^\$])|([^\s'"\+\,\(\)\>\<=\[\]\~]))+)/,/^(?:['](\\['"]|[^'"])+?['])/,/^(?:\()/,/^(?:\))/,/^(?:,)/,/^(?:\+)/,/^(?:-)/,/^(?:>=)/,/^(?:<=)/,/^(?:>)/,/^(?:<)/,/^(?:~\^)/,/^(?:~\$)/,/^(?:~)/,/^(?:([a-zA-Z])(?![a-zA-Z'"\,\(\)\>\<=\[\]\~]))/],
+conditions: {"reldate":{"rules":[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27],"inclusive":true},"INITIAL":{"rules":[0,1,2,3,4,5,6,7,8,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27],"inclusive":true}}
 });
 lexer.parseError = function(errStr, object) {
     var lines = errStr.split("\n"),
diff --git a/packages/nql-lang/src/nql.l b/packages/nql-lang/src/nql.l
index f8602b5d..0833c6ac 100644
--- a/packages/nql-lang/src/nql.l
+++ b/packages/nql-lang/src/nql.l
@@ -43,6 +43,7 @@ now(?=[-+]\d+[dwMyhms](?:{final}|$))                        { this.pushState('re
 '~^'                                                        return 'STARTSWITH';
 '~$'                                                        return 'ENDSWITH';
 '~'                                                         return 'CONTAINS';
+([a-zA-Z])(?![a-zA-Z'"\,\(\)\>\<=\[\]\~])                   return 'LITERAL';
 
 
 %%
diff --git a/packages/nql-lang/test/lexer.test.js b/packages/nql-lang/test/lexer.test.js
index 74d8b88b..9b694f06 100644
--- a/packages/nql-lang/test/lexer.test.js
+++ b/packages/nql-lang/test/lexer.test.js
@@ -165,6 +165,17 @@ describe('Lexer', function () {
             (function () {
                 lex('my&valu\'e!');
             }).should.throw(lexicalError);
+            lex('a').should.eql([
+                {token: 'LITERAL', matched: 'a'}
+            ]);
+            lex('a-b').should.eql([
+                {token: 'LITERAL', matched: 'a-b'}
+            ]);
+            lex('a+bc').should.eql([
+                {token: 'LITERAL', matched: 'a'},
+                {token: 'AND', matched: '+'},
+                {token: 'LITERAL', matched: 'bc'}
+            ]);
         });
 
         it('should separate NOT at beginning of literal', function () {
@@ -180,9 +191,6 @@ describe('Lexer', function () {
         });
 
         it('should NOT permit special chars inside a literal', function () {
-            (function () {
-                lex('t+st');
-            }).should.throw(lexicalError);
             (function () {
                 lex('t,st');
             }).should.throw(lexicalError);
diff --git a/packages/nql-lang/test/parser.test.js b/packages/nql-lang/test/parser.test.js
index 92e15c82..616e2991 100644
--- a/packages/nql-lang/test/parser.test.js
+++ b/packages/nql-lang/test/parser.test.js
@@ -627,5 +627,11 @@ describe('Parser', function () {
                 sinon.assert.calledTwice(relDateToAbsoluteSpy);
             });
         });
+
+        describe('Single character literals', function () {
+            it('can handle single character literals', function () {
+                parse('name:a').should.eql({name: 'a'});
+            });
+        });
     });
 });