Parser for Variables saved in a Map

[nank1ro]

Hi!

I have been struggling for quite some time to create a variable parser.
Here is a list of variables that I accept:

• var = 1
• another var = 2

the variable names are var and another var with the values 1 and 2.

I have correctly created the parser for these variables, but when I need to detect the use of these variables I cannot stop the parser at the variable name.

another var x 2 =

This should result in 4, but also the x is consumed.

It is possible to create a dynamic parser based on a list of strings (the name of the variables) ?

The parser I currently have is created inside an ExpressionBuilder and is created only once.
Is there a way to have a Parser.where that is rerun every time?

final emojiRegex = RegExp(
    r'[#*0-9]\uFE0F?\u20E3|[\xA9\xAE\u203C\u2049\u2122\u2139\u2194-\u2199\u21A9\u21AA\u231A\u231B\u2328\u23CF\u23ED-\u23EF\u23F1\u23F2\u23F8-\u23FA\u24C2\u25AA\u25AB\u25B6\u25C0\u25FB\u25FC\u25FE\u2600-\u2604\u260E\u2611\u2614\u2615\u2618\u2620\u2622\u2623\u2626\u262A\u262E\u262F\u2638-\u263A\u2640\u2642\u2648-\u2653\u265F\u2660\u2663\u2665\u2666\u2668\u267B\u267E\u267F\u2692\u2694-\u2697\u2699\u269B\u269C\u26A0\u26A7\u26AA\u26B0\u26B1\u26BD\u26BE\u26C4\u26C8\u26CF\u26D1\u26D3\u26E9\u26F0-\u26F5\u26F7\u26F8\u26FA\u2702\u2708\u2709\u270F\u2712\u2714\u2716\u271D\u2721\u2733\u2734\u2744\u2747\u2757\u2763\u27A1\u2934\u2935\u2B05-\u2B07\u2B1B\u2B1C\u2B55\u3030\u303D\u3297\u3299]\uFE0F?|[\u261D\u270C\u270D](?:\uFE0F|\uD83C[\uDFFB-\uDFFF])?|[\u270A\u270B](?:\uD83C[\uDFFB-\uDFFF])?|[\u23E9-\u23EC\u23F0\u23F3\u25FD\u2693\u26A1\u26AB\u26C5\u26CE\u26D4\u26EA\u26FD\u2705\u2728\u274C\u274E\u2753-\u2755\u2795-\u2797\u27B0\u27BF\u2B50]|\u26F9(?:\uFE0F|\uD83C[\uDFFB-\uDFFF])?(?:\u200D[\u2640\u2642]\uFE0F?)?|\u2764\uFE0F?(?:\u200D(?:\uD83D\uDD25|\uD83E\uDE79))?|\uD83C(?:[\uDC04\uDD70\uDD71\uDD7E\uDD7F\uDE02\uDE37\uDF21\uDF24-\uDF2C\uDF36\uDF7D\uDF96\uDF97\uDF99-\uDF9B\uDF9E\uDF9F\uDFCD\uDFCE\uDFD4-\uDFDF\uDFF5\uDFF7]\uFE0F?|[\uDF85\uDFC2\uDFC7](?:\uD83C[\uDFFB-\uDFFF])?|[\uDFC3\uDFC4\uDFCA](?:\uD83C[\uDFFB-\uDFFF])?(?:\u200D[\u2640\u2642]\uFE0F?)?|[\uDFCB\uDFCC](?:\uFE0F|\uD83C[\uDFFB-\uDFFF])?(?:\u200D[\u2640\u2642]\uFE0F?)?|[\uDCCF\uDD8E\uDD91-\uDD9A\uDE01\uDE1A\uDE2F\uDE32-\uDE36\uDE38-\uDE3A\uDE50\uDE51\uDF00-\uDF20\uDF2D-\uDF35\uDF37-\uDF7C\uDF7E-\uDF84\uDF86-\uDF93\uDFA0-\uDFC1\uDFC5\uDFC6\uDFC8\uDFC9\uDFCF-\uDFD3\uDFE0-\uDFF0\uDFF8-\uDFFF]|\uDDE6\uD83C[\uDDE8-\uDDEC\uDDEE\uDDF1\uDDF2\uDDF4\uDDF6-\uDDFA\uDDFC\uDDFD\uDDFF]|\uDDE7\uD83C[\uDDE6\uDDE7\uDDE9-\uDDEF\uDDF1-\uDDF4\uDDF6-\uDDF9\uDDFB\uDDFC\uDDFE\uDDFF]|\uDDE8\uD83C[\uDDE6\uDDE8\uDDE9\uDDEB-\uDDEE\uDDF0-\uDDF5\uDDF7\uDDFA-\uDDFF]|\uDDE9\uD83C[\uDDEA\uDDEC\uDDEF\uDDF0\uDDF2\uDDF4\uDDFF]|\uDDEA\uD83C[\uDDE6\uDDE8\uDDEA\uDDEC\uDDED\uDDF7-\uDDFA]|\uDDEB\uD83C[\uDDEE-\uDDF0\uDDF2\uDDF4\uDDF7]|\uDDEC\uD83C[\uDDE6\uDDE7\uDDE9-\uDDEE\uDDF1-\uDDF3\uDDF5-\uDDFA\uDDFC\uDDFE]|\uDDED\uD83C[\uDDF0\uDDF2\uDDF3\uDDF7\uDDF9\uDDFA]|\uDDEE\uD83C[\uDDE8-\uDDEA\uDDF1-\uDDF4\uDDF6-\uDDF9]|\uDDEF\uD83C[\uDDEA\uDDF2\uDDF4\uDDF5]|\uDDF0\uD83C[\uDDEA\uDDEC-\uDDEE\uDDF2\uDDF3\uDDF5\uDDF7\uDDFC\uDDFE\uDDFF]|\uDDF1\uD83C[\uDDE6-\uDDE8\uDDEE\uDDF0\uDDF7-\uDDFB\uDDFE]|\uDDF2\uD83C[\uDDE6\uDDE8-\uDDED\uDDF0-\uDDFF]|\uDDF3\uD83C[\uDDE6\uDDE8\uDDEA-\uDDEC\uDDEE\uDDF1\uDDF4\uDDF5\uDDF7\uDDFA\uDDFF]|\uDDF4\uD83C\uDDF2|\uDDF5\uD83C[\uDDE6\uDDEA-\uDDED\uDDF0-\uDDF3\uDDF7-\uDDF9\uDDFC\uDDFE]|\uDDF6\uD83C\uDDE6|\uDDF7\uD83C[\uDDEA\uDDF4\uDDF8\uDDFA\uDDFC]|\uDDF8\uD83C[\uDDE6-\uDDEA\uDDEC-\uDDF4\uDDF7-\uDDF9\uDDFB\uDDFD-\uDDFF]|\uDDF9\uD83C[\uDDE6\uDDE8\uDDE9\uDDEB-\uDDED\uDDEF-\uDDF4\uDDF7\uDDF9\uDDFB\uDDFC\uDDFF]|\uDDFA\uD83C[\uDDE6\uDDEC\uDDF2\uDDF3\uDDF8\uDDFE\uDDFF]|\uDDFB\uD83C[\uDDE6\uDDE8\uDDEA\uDDEC\uDDEE\uDDF3\uDDFA]|\uDDFC\uD83C[\uDDEB\uDDF8]|\uDDFD\uD83C\uDDF0|\uDDFE\uD83C[\uDDEA\uDDF9]|\uDDFF\uD83C[\uDDE6\uDDF2\uDDFC]|\uDFF3\uFE0F?(?:\u200D(?:\u26A7\uFE0F?|\uD83C\uDF08))?|\uDFF4(?:\u200D\u2620\uFE0F?|\uDB40\uDC67\uDB40\uDC62\uDB40(?:\uDC65\uDB40\uDC6E\uDB40\uDC67|\uDC73\uDB40\uDC63\uDB40\uDC74|\uDC77\uDB40\uDC6C\uDB40\uDC73)\uDB40\uDC7F)?)|\uD83D(?:[\uDC08\uDC26](?:\u200D\u2B1B)?|[\uDC3F\uDCFD\uDD49\uDD4A\uDD6F\uDD70\uDD73\uDD76-\uDD79\uDD87\uDD8A-\uDD8D\uDDA5\uDDA8\uDDB1\uDDB2\uDDBC\uDDC2-\uDDC4\uDDD1-\uDDD3\uDDDC-\uDDDE\uDDE1\uDDE3\uDDE8\uDDEF\uDDF3\uDDFA\uDECB\uDECD-\uDECF\uDEE0-\uDEE5\uDEE9\uDEF0\uDEF3]\uFE0F?|[\uDC42\uDC43\uDC46-\uDC50\uDC66\uDC67\uDC6B-\uDC6D\uDC72\uDC74-\uDC76\uDC78\uDC7C\uDC83\uDC85\uDC8F\uDC91\uDCAA\uDD7A\uDD95\uDD96\uDE4C\uDE4F\uDEC0\uDECC](?:\uD83C[\uDFFB-\uDFFF])?|[\uDC6E\uDC70\uDC71\uDC73\uDC77\uDC81\uDC82\uDC86\uDC87\uDE45-\uDE47\uDE4B\uDE4D\uDE4E\uDEA3\uDEB4-\uDEB6](?:\uD83C[\uDFFB-\uDFFF])?(?:\u200D[\u2640\u2642]\uFE0F?)?|[\uDD74\uDD90](?:\uFE0F|\uD83C[\uDFFB-\uDFFF])?|[\uDC00-\uDC07\uDC09-\uDC14\uDC16-\uDC25\uDC27-\uDC3A\uDC3C-\uDC3E\uDC40\uDC44\uDC45\uDC51-\uDC65\uDC6A\uDC79-\uDC7B\uDC7D-\uDC80\uDC84\uDC88-\uDC8E\uDC90\uDC92-\uDCA9\uDCAB-\uDCFC\uDCFF-\uDD3D\uDD4B-\uDD4E\uDD50-\uDD67\uDDA4\uDDFB-\uDE2D\uDE2F-\uDE34\uDE37-\uDE44\uDE48-\uDE4A\uDE80-\uDEA2\uDEA4-\uDEB3\uDEB7-\uDEBF\uDEC1-\uDEC5\uDED0-\uDED2\uDED5-\uDED7\uDEDC-\uDEDF\uDEEB\uDEEC\uDEF4-\uDEFC\uDFE0-\uDFEB\uDFF0]|\uDC15(?:\u200D\uD83E\uDDBA)?|\uDC3B(?:\u200D\u2744\uFE0F?)?|\uDC41\uFE0F?(?:\u200D\uD83D\uDDE8\uFE0F?)?|\uDC68(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:\uDC8B\u200D\uD83D)?\uDC68|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D(?:[\uDC68\uDC69]\u200D\uD83D(?:\uDC66(?:\u200D\uD83D\uDC66)?|\uDC67(?:\u200D\uD83D[\uDC66\uDC67])?)|[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uDC66(?:\u200D\uD83D\uDC66)?|\uDC67(?:\u200D\uD83D[\uDC66\uDC67])?)|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C(?:\uDFFB(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:\uDC8B\u200D\uD83D)?\uDC68\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D\uDC68\uD83C[\uDFFC-\uDFFF])))?|\uDFFC(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:\uDC8B\u200D\uD83D)?\uDC68\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D\uDC68\uD83C[\uDFFB\uDFFD-\uDFFF])))?|\uDFFD(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:\uDC8B\u200D\uD83D)?\uDC68\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D\uDC68\uD83C[\uDFFB\uDFFC\uDFFE\uDFFF])))?|\uDFFE(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:\uDC8B\u200D\uD83D)?\uDC68\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D\uDC68\uD83C[\uDFFB-\uDFFD\uDFFF])))?|\uDFFF(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:\uDC8B\u200D\uD83D)?\uDC68\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D\uDC68\uD83C[\uDFFB-\uDFFE])))?))?|\uDC69(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:\uDC8B\u200D\uD83D)?[\uDC68\uDC69]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D(?:[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uDC66(?:\u200D\uD83D\uDC66)?|\uDC67(?:\u200D\uD83D[\uDC66\uDC67])?|\uDC69\u200D\uD83D(?:\uDC66(?:\u200D\uD83D\uDC66)?|\uDC67(?:\u200D\uD83D[\uDC66\uDC67])?))|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C(?:\uDFFB(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:[\uDC68\uDC69]|\uDC8B\u200D\uD83D[\uDC68\uDC69])\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D[\uDC68\uDC69]\uD83C[\uDFFC-\uDFFF])))?|\uDFFC(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:[\uDC68\uDC69]|\uDC8B\u200D\uD83D[\uDC68\uDC69])\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D[\uDC68\uDC69]\uD83C[\uDFFB\uDFFD-\uDFFF])))?|\uDFFD(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:[\uDC68\uDC69]|\uDC8B\u200D\uD83D[\uDC68\uDC69])\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D[\uDC68\uDC69]\uD83C[\uDFFB\uDFFC\uDFFE\uDFFF])))?|\uDFFE(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:[\uDC68\uDC69]|\uDC8B\u200D\uD83D[\uDC68\uDC69])\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D[\uDC68\uDC69]\uD83C[\uDFFB-\uDFFD\uDFFF])))?|\uDFFF(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D\uD83D(?:[\uDC68\uDC69]|\uDC8B\u200D\uD83D[\uDC68\uDC69])\uD83C[\uDFFB-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83D[\uDC68\uDC69]\uD83C[\uDFFB-\uDFFE])))?))?|\uDC6F(?:\u200D[\u2640\u2642]\uFE0F?)?|\uDD75(?:\uFE0F|\uD83C[\uDFFB-\uDFFF])?(?:\u200D[\u2640\u2642]\uFE0F?)?|\uDE2E(?:\u200D\uD83D\uDCA8)?|\uDE35(?:\u200D\uD83D\uDCAB)?|\uDE36(?:\u200D\uD83C\uDF2B\uFE0F?)?)|\uD83E(?:[\uDD0C\uDD0F\uDD18-\uDD1F\uDD30-\uDD34\uDD36\uDD77\uDDB5\uDDB6\uDDBB\uDDD2\uDDD3\uDDD5\uDEC3-\uDEC5\uDEF0\uDEF2-\uDEF8](?:\uD83C[\uDFFB-\uDFFF])?|[\uDD26\uDD35\uDD37-\uDD39\uDD3D\uDD3E\uDDB8\uDDB9\uDDCD-\uDDCF\uDDD4\uDDD6-\uDDDD](?:\uD83C[\uDFFB-\uDFFF])?(?:\u200D[\u2640\u2642]\uFE0F?)?|[\uDDDE\uDDDF](?:\u200D[\u2640\u2642]\uFE0F?)?|[\uDD0D\uDD0E\uDD10-\uDD17\uDD20-\uDD25\uDD27-\uDD2F\uDD3A\uDD3F-\uDD45\uDD47-\uDD76\uDD78-\uDDB4\uDDB7\uDDBA\uDDBC-\uDDCC\uDDD0\uDDE0-\uDDFF\uDE70-\uDE7C\uDE80-\uDE88\uDE90-\uDEBD\uDEBF-\uDEC2\uDECE-\uDEDB\uDEE0-\uDEE8]|\uDD3C(?:\u200D[\u2640\u2642]\uFE0F?|\uD83C[\uDFFB-\uDFFF])?|\uDDD1(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\uD83C[\uDF3E\uDF73\uDF7C\uDF84\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83E\uDDD1))|\uD83C(?:\uDFFB(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D(?:\uD83D\uDC8B\u200D)?\uD83E\uDDD1\uD83C[\uDFFC-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF84\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83E\uDDD1\uD83C[\uDFFB-\uDFFF])))?|\uDFFC(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D(?:\uD83D\uDC8B\u200D)?\uD83E\uDDD1\uD83C[\uDFFB\uDFFD-\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF84\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83E\uDDD1\uD83C[\uDFFB-\uDFFF])))?|\uDFFD(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D(?:\uD83D\uDC8B\u200D)?\uD83E\uDDD1\uD83C[\uDFFB\uDFFC\uDFFE\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF84\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83E\uDDD1\uD83C[\uDFFB-\uDFFF])))?|\uDFFE(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D(?:\uD83D\uDC8B\u200D)?\uD83E\uDDD1\uD83C[\uDFFB-\uDFFD\uDFFF]|\uD83C[\uDF3E\uDF73\uDF7C\uDF84\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83E\uDDD1\uD83C[\uDFFB-\uDFFF])))?|\uDFFF(?:\u200D(?:[\u2695\u2696\u2708]\uFE0F?|\u2764\uFE0F?\u200D(?:\uD83D\uDC8B\u200D)?\uD83E\uDDD1\uD83C[\uDFFB-\uDFFE]|\uD83C[\uDF3E\uDF73\uDF7C\uDF84\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E(?:[\uDDAF-\uDDB3\uDDBC\uDDBD]|\uDD1D\u200D\uD83E\uDDD1\uD83C[\uDFFB-\uDFFF])))?))?|\uDEF1(?:\uD83C(?:\uDFFB(?:\u200D\uD83E\uDEF2\uD83C[\uDFFC-\uDFFF])?|\uDFFC(?:\u200D\uD83E\uDEF2\uD83C[\uDFFB\uDFFD-\uDFFF])?|\uDFFD(?:\u200D\uD83E\uDEF2\uD83C[\uDFFB\uDFFC\uDFFE\uDFFF])?|\uDFFE(?:\u200D\uD83E\uDEF2\uD83C[\uDFFB-\uDFFD\uDFFF])?|\uDFFF(?:\u200D\uD83E\uDEF2\uD83C[\uDFFB-\uDFFE])?))?)');


final variables = <({String name, int lineNumber}), AtomExpression>{};


  late final Parser<String> emojiParser =
      PatternParser(emojiRegex, 'Emoji expected').map((value) => value[0]!);


  late final Parser<String> variable = () {
    return seq3(
            char(' ').star(),
            [
              emojiParser,
              letter(),
            ].toChoiceParser(),
            [emojiParser, pattern('a-zA-Z_0-9 ')]
                .toChoiceParser()
                .star()
                .optional())
        .flatten()
        .map((value) => value.trim());
  }();

  late final Parser<String> variableDeclaration = () {
    return seq2(variable, char('=').trim()).map((value) => value.first);
  }();


 // Returns the value of a variable if the name of that variable exists
  late final Parser<AtomExpression> variableUsageParser = () {
    return variable.where((value) {
      final sublist = variables.keys
          .where((v) => v.lineNumber < parsingLineNumber)
          .toList();
      return sublist.where((v) => v.name == value).isNotEmpty;
    }).map((name) {
      final sublist = variables.keys
          .where((v) => v.lineNumber < parsingLineNumber)
          .toList()
          .reversed;
      final key = sublist.firstWhere((v) => v.name == name);
      final value = variables[key]!;
      return AtomExpressionVariable(name: name, value: value);
    });
  }();

If you need it I can prepare some working code, but I need some time to correctly extract just this functionality

[renggli]

I am not entirely sure I understand the question, or the input language you are trying to parse.

That said, with the continuation parser you can dynamically create new parsers at parse-time. The following example first only parses first and second; and then in the last line after changing the list of variables it also accepts third:

final variables = ['first', 'second'];
final parser = failure<String>().callCC((continuation, context) => variables
      .map((each) => each.toParser())
      .toChoiceParser()
      .parseOn(context));

expect(parser, isParseSuccess('first'));
expect(parser, isParseSuccess('second'));
expect(parser, isParseFailure('third'));

variables.add('third');
expect(parser, isParseSuccess('third'));

[nank1ro]

It worked perfectly. It's exactly what I wanted! Thank you so much!