nearley - lambda

lambda.ne

# lambda
# 
# see my Michaelson book

# nearley
#nearleyc lambda.ne -o lambda.js
#nearley-test -q -i '' lambda.js

# https://github.com/kach/nearley/blob/master/builtin/whitespace.ne
# Whitespace: `_` is optional, `__` is mandatory.
#_  -> wschar:* {% function(d) {return null;} %}
#__ -> wschar:+ {% function(d) {return null;} %}
#wschar -> [ \t\n\v\f] {% id %}

@builtin "whitespace.ne" # `_` means arbitrary amount of whitespace

# based on: https://medium.com/@gajus/parsing-absolutely-anything-in-javascript-using-earley-algorithm-886edcc31e5e
@{%
const flatten = d => {
  return d.reduce(
    (a, b) => {
      return a.concat(b);
    },
    []
  );
}

// this doesn't seem to do anything
const flatten2 = d => {
  return flatten(flatten(d));
}

const filter = d => {
  return d.filter((token) => {
    return token !== null;
  });
}

const selectorBody = (d, i, reject) => {
  const tokens = filter(d);
  if (!tokens.length) {
    return reject;
  }
  return flatten(tokens);
}
%}

# 2.2 Syntax
expression -> name | function | application {% selectorBody %}
function -> LAMBDA name DOT body {% selectorBody %}
body -> expression {% selectorBody %} #{% function(d) {return d } %}
application -> "(" function_expression __ argument_expression ")"
function_expression -> expression
argument_expression -> expression
name -> [a-zA-Z0-9-_+]:+ #{% function(d) {return d } %}
LAMBDA -> "λ" {% function(d) {return "" } %}
DOT -> "." {% function(d) {return " => " } %}
__ -> " " {% function(d) {return " " } %}

# KSW added
#ParenthOpen             -> [ "(" ] {% function(d) {return null;} %}
#ParenthClose            -> [ ")" ] {% function(d) {return null;} %}

xholonWorkbook.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--Xholon Workbook http://www.primordion.com/Xholon/gwt/ MIT License, Copyright (C) Ken Webb, Mon Jul 10 2023 09:54:16 GMT-0400 (GMT-04:00)-->
<XholonWorkbook>

<Notes><![CDATA[
Xholon
------
Title: nearley - lambda
Description: 
Url: http://www.primordion.com/Xholon/gwt/
InternalName: c22cb0b3d44fd87d6ba2ce6328c74ea5
Keywords: 

My Notes
--------
10 July 2023

Demonstrate the use of nearley in a browser and in Xholon.
Use my new nearley lambda grammar, that works with nodejs.

http://0.0.0.0:3001/wb/editwb.html
http://0.0.0.0:3001/wb/editwb.html?app=nearley+-+lambda&src=lstr

http://0.0.0.0:3001/Xholon.html?app=nearley+-+lambda&src=lstr&gui=clsc&jslib=nearley/nearley,nearley/lambdaXH01

// does not work
https://www.primordion.com/Xholon/gwt/Xholon.html?app=nearley+-+lambda&src=lstr&gui=clsc

###The lambda grammar
The lambda grammar is not yet complete.
It works for some simple cases.

###The version of nearley
I already had nearley.js in my local Xholon src/public/lib/nearley folder
nearley github site has a different .js file (newer/older ???)
 - I have included this in Xholon src/public/lib/nearley as nearleyGHlatest.js

###Dev Tools code:
(() => {
  const example = [
  "λx.x",
  "λx.λy.λz.x",
  "λfirst.λsecond.first",
  "λs.(s s)"
  ];

  // Create a Parser object from our grammar.
  const parser = new nearley.Parser(nearley.Grammar.fromCompiled(grammar));

  // Parse something!
  parser.feed(example[2]);

  // parser.results is an array of possible parsings.
  const arr = parser.results.flat(Infinity).join('');
  console.log(`const funk = ${arr}`); // const funk = first => second => first
})()

###To run locally
~/gwtspace/Xholon/Xholon/war$ python3 -m http.server 3001
Serving HTTP on 0.0.0.0 port 3001 (http://0.0.0.0:3001/) ...


References
----------
() Greg Michaelson, An Introduction to Functional Programming Through Lambda Calculus, Dover, 2011

() https://nearley.js.org/
() https://omrelli.ug/nearley-playground/
() https://github.com/kach/nearley

() my folders
   ~/gwtspace/Xholon/Xholon/nearley/lambda
   ~/nodespace/nearleyKSW
   ~/gwtspace/Xholon/Xholon/src/org/public/lib/nearley

() my notebook
   9 July 2023

]]></Notes>  

<_-.XholonClass>
  <PhysicalSystem/>
  
  <Lambda/>
  
</_-.XholonClass>

<xholonClassDetails>
  <!--<Block>
    <port name="height" connector="Height"/>
  </Block>-->
</xholonClassDetails>

<PhysicalSystem>
  <Lambda/>
</PhysicalSystem>

<Lambdabehavior implName="org.primordion.xholon.base.Behavior_gwtjs"><![CDATA[
  const example = [
  "λx.x",
  "λx.λy.λz.x",
  "λfirst.λsecond.first",
  "λs.(s s)"
  ];
                                                                       
  // Create a Parser object from our grammar.
  const parser = new $wnd.nearley.Parser($wnd.nearley.Grammar.fromCompiled($wnd.grammar));

  // Parse something!
  parser.feed(example[2]);

  // parser.results is an array of possible parsings.
  const arr = parser.results.flat(Infinity).join('');
  console.log(`const funk = ${arr}`); // const funk = first => second => first
  // this works
  
  $wnd.xh.root().println(`const funk = ${arr}`);
  // this works
  
  //# sourceURL=Lambdabehavior.js
]]></Lambdabehavior>

<SvgClient><Attribute_String roleName="svgUri"><![CDATA[data:image/svg+xml,
<svg width="100" height="50" xmlns="http://www.w3.org/2000/svg">
  <g>
    <title>Lambda</title>
    <rect id="PhysicalSystem/Lambda" fill="#98FB98" height="50" width="50" x="25" y="0"/>
    <g>
      <title>Lambda</title>
      <rect id="PhysicalSystem/Lambda" fill="#6AB06A" height="50" width="10" x="80" y="0"/>
    </g>
  </g>
</svg>
]]></Attribute_String><Attribute_String roleName="setup">${MODELNAME_DEFAULT},${SVGURI_DEFAULT}</Attribute_String></SvgClient>

</XholonWorkbook>