### Setup development environment

Source: https://github.com/ohmjs/ohm/blob/main/packages/compiler/README.md

Install project dependencies for development.

```bash
pnpm install
```

--------------------------------

### Customized AST Transformation Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/extras.md

This code snippet demonstrates how to create an AST from a matched expression using a custom mapping. It shows the initial setup for transforming CST to AST with specific rule configurations.

```javascript
// create ohm, g, match and toAST
const ast = toAST(match, {
  Equation: {content: 0},
  AddExpr: {type: 'Expression', expr1: 0, op: 1, expr2: 2},
});
```

--------------------------------

### Install Ohm with pnpm

Source: https://github.com/ohmjs/ohm/blob/main/README.md

Install the ohm-js package using pnpm.

```bash
pnpm add ohm-js
```

--------------------------------

### toAST Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/extras.md

Example demonstrating the use of toAST to convert a MatchResult to an AST.

```javascript
const ohm = require('ohm-js');
const g = ohm.grammar(
  `
    G {
      Equation = AddExpr
      AddExpr = number "+" number
      number = digit+
    }
  `
);
const match = g.match('24 +  6');
const toAST = require('ohm-js/extras').toAST;
const ast = toAST(match);

```

--------------------------------

### Example: Compile and specify output file

Source: https://github.com/ohmjs/ohm/blob/main/doc/docker.md

An example demonstrating how to compile a grammar file and specify the output file name for the WASM module.

```sh
docker run --rm -v $(pwd):/local ohmjs/ohm:latest compile -o arithmetic.wasm arithmetic.ohm
```

--------------------------------

### Matching with a Specific Start Rule

Source: https://github.com/ohmjs/ohm/blob/main/examples/math/index.html

Shows how to specify a start rule for the match() method, overriding the default start rule.

```javascript
g.match(' ( \t123 ) ', 'PriExp').succeeded(); // evaluates to `true`
```

--------------------------------

### Install Ohm with Yarn

Source: https://github.com/ohmjs/ohm/blob/main/README.md

Install the ohm-js package using Yarn.

```bash
yarn add ohm-js
```

--------------------------------

### Install dependencies

Source: https://github.com/ohmjs/ohm/blob/main/packages/compiler/README.md

Install @ohm-js/compiler as a dev dependency and ohm-js for runtime.

```bash
npm install --save-dev @ohm-js/compiler
npm install ohm-js
```

--------------------------------

### Example Semantic Actions with Implementation

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

Example semantic actions with placeholder implementations filled in.

```javascript
return lastName.x().toUpperCase() + ', ' + firstName.x();
        return this.sourceString;
```

--------------------------------

### Install Ohm with npm

Source: https://github.com/ohmjs/ohm/blob/main/README.md

Install the ohm-js package using npm.

```bash
npm install ohm-js
```

--------------------------------

### Generated AST Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/extras.md

The resulting AST from the toAST example.

```json
{
    "type": "AddExpr",  // 'type' automatically taken from the rule name
    "0": "24",          // First part (position 0) matched by AddExpr rule
    "2": "6"            // Third part (position 2) matched by AddExpr rule
  }

```

--------------------------------

### Instantiating a Grammar

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

Example of instantiating a Grammar using ohm.grammar.

```javascript
const parentDef = String.raw`
  Parent {
    start = "parent"
  }
`;
const parentGrammar = ohm.grammar(parentDef);
```

--------------------------------

### Install development dependencies

Source: https://github.com/ohmjs/ohm/blob/main/doc/contributor-guide.md

Installs the necessary development dependencies using pnpm.

```bash
cd ohm
pnpm install
```

--------------------------------

### Minimal Docker setup for macOS

Source: https://github.com/ohmjs/ohm/blob/main/doc/docker.md

Steps to set up Docker, Colima, and Docker Compose on macOS.

```sh
brew install colima docker docker-compose docker-credential-helper
colima start
```

--------------------------------

### Parameterized Rule Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/syntax-reference.md

Example of defining a parameterized rule in Ohm.

```ohm
Repeat<x> = x x
```

--------------------------------

### Install ohm-grammar-ecmascript

Source: https://github.com/ohmjs/ohm/blob/main/examples/ecmascript/README.md

Installs the ECMAScript grammars package using NPM.

```bash
npm install ohm-grammar-ecmascript
```

--------------------------------

### Syntactic Rule Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/syntax-reference.md

Example of syntactic rules for an Array grammar.

```ohm
Array = "[" "]"  -- empty
      | "[" Elements "]"  -- nonEmpty
Elements = Element ("," Element)*
```

--------------------------------

### Grammar for asIteration Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

A simple Ohm grammar demonstrating a ListOf expression.

```ohm
G {
  Start = ListOf<letter, ",">
}
```

--------------------------------

### Example Semantic Actions

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

An example of semantic actions for the Name grammar, demonstrating how to compute values for parse nodes.

```javascript
const actions = {
  FullName(firstName, lastName) { ... },
  name(parts) { ... }
};
```

--------------------------------

### Install @ohm-js/cli

Source: https://github.com/ohmjs/ohm/blob/main/doc/typescript.md

Install the Ohm CLI package as a development dependency.

```bash
npm install -D @ohm-js/cli
```

--------------------------------

### Usage Example

Source: https://github.com/ohmjs/ohm/blob/main/packages/compiler/test/go/README.md

Instantiates a grammar from compiled Wasm bytes, matches input against it, and retrieves the CST root if the match succeeded.

```go
// Instantiate a grammar from compiled Wasm bytes
wasmBytes, _ := os.ReadFile("path/to/grammar.wasm")
g, err := NewGrammar(ctx, wasmBytes)
defers g.Close()

// Match input against the grammar (optional second arg is start rule)
result, err := g.Match("var x = 1;")
defers result.Close()

if result.Succeeded() {
    cstRoot, err := result.GetCstRoot()
    // ...walk the tree
}
```

--------------------------------

### Getting help from the Docker image

Source: https://github.com/ohmjs/ohm/blob/main/doc/docker.md

Command to display usage information for the Ohm.js Docker image.

```sh
docker run --rm ohmjs/ohm:latest help
```

--------------------------------

### Example Usage

Source: https://github.com/ohmjs/ohm/blob/main/packages/es-grammars/README.md

Demonstrates how to import and use an ES grammar to match JavaScript code.

```javascript
import {es2020} from '@ohm-js/es-grammars';
es2020.match('() => 3').succeeded(); // true
```

--------------------------------

### Usage Example

Source: https://github.com/ohmjs/ohm/blob/main/examples/ecmascript/README.md

Demonstrates how to import and use the ES5 grammar from the ohm-grammar-ecmascript package to match ECMAScript code.

```javascript
import * as es5 from 'ohm-grammar-ecmascript';
const result = es5.grammar.match('var x = 3; console.log(x);');
assert(result.succeeded());
```

--------------------------------

### JavaScript Setup and Event Handling

Source: https://github.com/ohmjs/ohm/blob/main/examples/incremental/index.html

JavaScript code for setting up the CodeMirror editor, handling grammar parsing, and updating statistics.

```javascript
'use strict';
const grammarSource = String.raw` F { Exp = let PriPat "=" Exp in Exp -- let | let rec ident "=" Exp in Exp -- letrec | let rec "(" ident ":" Type ")" "=" Exp in Exp -- typedLetrec | fun PriPat+ "->" Exp -- fun | if Exp then Exp else Exp -- if | match Exp with "|"? NonemptyListOf<PatAndExp, "|"> -- match

  PatAndExp = Pat "->" Exp
  Pat = ctor PriPat -- datum
      | PriPat PriPat -- emptyDatum
      | "(" Pat ")" -- paren
      | "(" Pat ":" Type ")" -- typed
      | "(" ListOf<Pat, ","> ")" -- tuple
      | "[" ListOf<Pat, ";"> "]" -- list
      | "_" -- wild
      | ident -- ident
      | number -- number
      | trueK -- true
      | falseK -- false

  OrExp = OrExp "||" AndExp -- or
        | AndExp
  AndExp = AndExp "&&" EqExp -- and
         | EqExp
  EqExp = RelExp "=" RelExp -- eq
        | RelExp "!=" RelExp -- neq
        | RelExp
  RelExp = AddExp "<" AddExp -- lt
         | AddExp ">" AddExp -- gt
         | AddExp
  AddExp = AddExp "+" MulExp -- plus
         | AddExp "-" MulExp -- minus
         | MulExp
  MulExp = MulExp "*" CallExp -- times
         | MulExp "/" CallExp -- divide
         | MulExp "%" CallExp -- modulus
         | CallExp
  CallExp = CallExp PriExp -- call
          | UnExp
  UnExp = "+" DatumExp -- pos
        | "-" DatumExp -- neg
        | delay DatumExp -- delay
        | force DatumExp -- force
        | DatumExp
  DatumExp = ctor PriExp -- datum
           | PriExp
  PriExp = ctor -- emptyDatum
         | "(" Exp ")" -- paren
         | "(" Exp ":" Type ")" -- typed
         | "(" ListOf<Exp, ","> ")" -- tuple
         | "[" Exp "|" Pat "<-" Exp ("," Exp)? "]" -- listComp
         | "[" ListOf<Exp, ";"> "]" -- list
         | ident -- ident
         | number -- number
         | trueK -- true
         | falseK -- false

  Type = FunType
  FunType = TupleType "->" FunType -- fun
          | TupleType
  TupleType = ListOrDelayedType ("*" ListOrDelayedType)+ -- tuple
            | ListOrDelayedType
  ListOrDelayedType = ListOrDelayedType list -- list
                    | ListOrDelayedType delayed -- delayed
                    | PriType
  PriType = "(" Type ")" -- paren
          | int -- int
          | bool -- bool
          | unit -- unit
          | typeVar

  typeVar (a type variable) = "'" ident

// Lexical rules
ident (an identifier) = ~keyword lower alnum*
ctor (a data constructor) = ~keyword upper alnum*
number (a number) = digit* "." digit+ -- fract
                | digit+ -- whole

fun = "fun" ~alnum
let = "let" ~alnum
rec = "rec" ~alnum
in = "in" ~alnum
if = "if" ~alnum
then = "then" ~alnum
else = "else" ~alnum
match = "match" ~alnum
with = "with" ~alnum
trueK = "true" ~alnum
falseK = "false" ~alnum
delay = "delay" ~alnum
force = "force" ~alnum
int = "int" ~alnum
bool = "bool" ~alnum
unit = "unit" ~alnum
list = "list" ~alnum
delayed = "delayed" ~alnum

keyword = fun | let | rec | in | if | then | else | match | with | trueK | falseK | delay | force | int | bool | unit | list | delayed

space += comment
comment = "/*" (~"*/" any)* "*/" -- multiLine
        | "//" (~"\n" any)* -- singleLine
}
`;

// Declare some helpers
function time(fn) {
  const startTime = Date.now();
  fn();
  const endTime = Date.now();
  return endTime - startTime;
}

function spaces(n) {
  let ss = '';
  while (n-- > 0) {
    ss += ' ';
  }
  return ss;
}

// Declare some variables to keep stats, etc.
const parseTimes = [];
const getExpectedTextTimes = [];

function updateStats() {
  const totalParseTime = parseTimes.reduce((x, y) => x + y, 0);
  msPerParseSpan.innerText = (totalParseTime / parseTimes.length).toFixed(2);
  msForLastParseSpan.innerText = parseTimes[parseTimes.length - 1];
  parseTimesSparkline.setAttribute('data-values', parseTimes);

  const totalGetExpectedTextTime = getExpectedTextTimes.reduce((x, y) => x + y, 0);
  numGetExpectedTextCallsSpan.innerText = getExpectedTextTimes.length;
  totalGetExpectedTextTimeSpan.innerText = totalGetExpectedTextTime;
  msPerGetExpectedTextSpan.innerText = (totalGetExpectedTextTime / getExpectedTextTimes.length).toFixed(2);
  getExpectedTextTimesSparkline.setAttribute('data-values', getExpectedTextTimes);

  updateSparklines();
}

// Set up our CodeMirror instance, and react to changes in the input
const editor = CodeMirror.fromTextArea(myTextArea, {
  lineNumbers: true
});

const g = ohm.grammar(grammarSource);
const m = g.matcher();

let parseErrorWidget;

editor.on('beforeChange', function(cmInstance, changeObj) {
  const insertedText = changeObj.text.join('\n');
  const fromIdx = editor.indexFromPos(changeObj.from);
  const toIdx = editor.indexFromPos(changeObj.to);
  m.replaceInputRange(fromIdx, toIdx, inserte
```

--------------------------------

### Instantiating Grammars with Inheritance

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

Example of instantiating a new grammar, Child, that inherits from the Parent grammar using ohm.grammars.

```javascript
const childDef = String.raw`
  Child <: Parent {
    start := "child"
  }
`;
const childGrammar = ohm.grammars(childDef, {Parent: parentGrammar});
console.log(Object.keys(childGrammar));
// > [ 'Child' ]
```

--------------------------------

### Exporting grammars and semantics

Source: https://github.com/ohmjs/ohm/blob/main/doc/publishing-grammars.md

Example of how to export grammars and semantics from a module, and how to use them.

```javascript
const {python2} = require('./your-python-package');
const result = python2.grammar.match('print 3');
python2.semantics(result).eval();
```

--------------------------------

### Node Methods and Properties

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

Examples of using various methods and properties of a parse node.

```javascript
n.child(idx: number) => Node
n.isTerminal() => boolean
n.isIteration() => boolean
n.children: Array
n.ctorName: string
n.source: Interval
n.sourceString: string
n.numChildren: number
n.isOptional() => boolean
```

--------------------------------

### Analyzing image size from inside the container

Source: https://github.com/ohmjs/ohm/blob/main/doc/docker.md

Steps to install and run `ncdu` inside the container to analyze disk usage.

```sh
apt-get update
apt-get install -y ncdu
ncdu /
```

--------------------------------

### Operator precedence with left-recursive rules

Source: https://github.com/ohmjs/ohm/blob/main/doc/patterns-and-pitfalls.md

Example demonstrating how to handle operator precedence in Ohm using left-recursive rules.

```ohm
exp = addExp

addExp = addExp "+" mulExp  -- plus
       | addExp "-" mulExp  -- minus
       | mulExp

mulExp = mulExp "*" priExp  -- times
       | mulExp "/" priExp  -- divide
       | priExp
```

--------------------------------

### C-style comments

Source: https://github.com/ohmjs/ohm/blob/main/doc/patterns-and-pitfalls.md

Example of defining C-style multiline comments.

```ohm
comment = "/*" (~"*/" any)* "*/"
```

--------------------------------

### Example Grammar

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

A simple grammar defining a Name and FullName structure.

```ohm
Name {
  FullName = name name
  name = (letter | "-" | ".")+
}
```

--------------------------------

### Basic Grammar Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/syntax-reference.md

A simple Ohm grammar named 'Arithmetic' with a single rule 'Expr' that matches the literal string '1 + 1'.

```ohm
Arithmetic {
  Expr = "1 + 1"
}
```

--------------------------------

### Trailer code for _PyPegen_parse

Source: https://github.com/ohmjs/ohm/blob/main/packages/lang-python/python-peg-grammar.txt

This is a C code snippet that initializes keywords and runs the parser based on the start rule.

```c
void *
_PyPegen_parse(Parser *p)
{
    // Initialize keywords
    p->keywords = reserved_keywords;
    p->n_keyword_lists = n_keyword_lists;
    p->soft_keywords = soft_keywords;

    // Run parser
    void *result = NULL;
    if (p->start_rule == Py_file_input) {
        result = file_rule(p);
    } else if (p->start_rule == Py_single_input) {
        result = interactive_rule(p);
    } else if (p->start_rule == Py_eval_input) {
        result = eval_rule(p);
    } else if (p->start_rule == Py_func_type_input) {
        result = func_type_rule(p);
    }

    return result;
}
```

--------------------------------

### Instantiating and Using the Grammar

Source: https://github.com/ohmjs/ohm/blob/main/examples/math/index.html

Demonstrates how to instantiate an Ohm grammar from a source string and use its match() method to recognize inputs.

```javascript
const g = ohm.grammar(source);

g.match('1+2*3').succeeded(); // evaluates to `true`
g.match('1+2*3').failed(); // evaluates to `false`
g.match('I CAN HAS CHEEZBURGER?').succeeded(); // evaluates to `false`
g.match('I CAN HAS CHEEZBURGER?').failed(); // evaluates to `true`
```

--------------------------------

### Use Ohm with Deno

Source: https://github.com/ohmjs/ohm/blob/main/README.md

Import Ohm from an unpkg URL for use with Deno.

```js
import * as ohm from 'https://unpkg.com/ohm-js@17';
```

--------------------------------

### Using the match() method

Source: https://github.com/ohmjs/ohm/blob/main/README.md

This example shows how to use the `match()` method of an instantiated grammar object to recognize input and check if the match was successful.

```javascript
const userInput = 'Hello';
const m = myGrammar.match(userInput);
if (m.succeeded()) {
  console.log('Greetings, human.');
} else {
  console.log("That's not a greeting!");
}
```

--------------------------------

### Undeclared Grammar Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/errors.md

Example demonstrating how to fix an UndeclaredGrammar error by passing a namespace argument to ohm.grammar().

```javascript
const ns = {};
ns.G1 = ohm.grammar('G1 {}');
const g2 = ohm.grammar('G2 <: G1 {}', ns);
```

--------------------------------

### Invalid Lambda Syntax Examples

Source: https://github.com/ohmjs/ohm/blob/main/packages/lang-python/python-peg-grammar.txt

Examples of invalid syntax related to lambda parameters, including default values, bare '*', and double '**'.

```python
invalid_lambda_star_etc:
    | '*' (':' | ',' (':' | '**')) { RAISE_SYNTAX_ERROR("named parameters must follow bare *") }
    | '*' lambda_param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-positional parameter cannot have default value") }
    | '*' (lambda_param_no_default | ',') lambda_param_maybe_default* a='*' (lambda_param_no_default | ',') {
        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "* may appear only once") }
invalid_lambda_kwds:
    | '**' lambda_param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-keyword parameter cannot have default value") }
    | '**' lambda_param ',' a=lambda_param { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "parameters cannot follow var-keyword parameter") }
    | '**' lambda_param ',' a[Token*]=('*'|'**'|'/') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "parameters cannot follow var-keyword parameter") }
```

--------------------------------

### Multiline comments

Source: https://github.com/ohmjs/ohm/blob/main/doc/syntax-reference.md

Example of multiline comments in Ohm grammars.

```ohm
/*
  Note: Punctuator and DivPunctuator (see https://es5.github.io/x7.html#x7.7) are
  not currently used by this grammar.
*/

```

--------------------------------

### Single-line comments

Source: https://github.com/ohmjs/ohm/blob/main/doc/syntax-reference.md

Example of single-line comments in Ohm grammars.

```ohm
booleanLiteral = ("true" | "false") // TODO: Should we support "True"/"False" as well?

```

```ohm
// For semantics on how decimal literals are constructed, see section 7.8.3

```

--------------------------------

### Memoization Visualization Canvas Setup

Source: https://github.com/ohmjs/ohm/blob/main/packages/memoviz-demo/index.html

Sets up the canvas element for drawing the memoization visualization, adjusting for device pixel ratio and screen size.

```javascript
const canvas = document.querySelector("canvas");
const ctx = canvas.getContext("2d");

// Get the DPR and size of the canvas
const dpr = window.devicePixelRatio;

// const rect = canvas.getBoundingClientRect();

// Set the "actual" size of the canvas
canvas.width = window.innerWidth * dpr;
canvas.height = window.innerHeight * dpr;

canvas.style.width = `${window.innerWidth}px`;
canvas.style.height = `${window.innerHeight}px`;

// prettier-ignore
const data = [
  [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
  [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
  [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
  [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
  [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
  [1,1,0,0,0,1,0,0,0,0,1,1,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
];
```

--------------------------------

### Testing asIteration Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

Assertion to verify the output of the asIteration operation.

```javascript
assert.deepEqual(
  s(g_asIteration.match('a, b, c')).upper(),
  ['A', 'B', 'C']
);
```

--------------------------------

### Semantics for asIteration Example

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

An operation added to a semantics to process a ListOf expression using asIteration.

```javascript
s.addOperation('upper()', {
  Start(list) {
    return list.asIteration().children.map(c => c.upper());
  },
  letter(l) {
    return this.sourceString.toUpperCase();
  }
});
```

--------------------------------

### Ohm-js Demo Page

Source: https://github.com/ohmjs/ohm/blob/main/packages/memoviz-demo/index.html

This HTML file serves as a demo page for the Ohm-js library, demonstrating its usage and features.

```html
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>Ohm Demo</title>
  <style>
    body { font-family: sans-serif; }
    .demo-container { display: flex; }
    .controls { flex: 1; padding-right: 20px; }
    .output { flex: 1; border-left: 1px solid #ccc; padding-left: 20px; }
    textarea { width: 95%; height: 150px; margin-bottom: 10px; }
    pre { background-color: #f4f4f4; padding: 10px; border: 1px solid #ddd; }
  </style>
</head>
<body>
  <h1>Ohm-js Demo</h1>
  <p>This page demonstrates the capabilities of the Ohm-js library.</p>

  <div class="demo-container">
    <div class="controls">
      <h2>Grammar</h2>
      <textarea id="grammar-input">start = expr
  expr = term (("+" | "-") term)*
  term = factor (("*" | "/") factor)*
  factor = number | "(" expr ")"
  number = ~
```

```javascript
const ohm = require('ohm-js');

const grammarSource = `
start = expr
  expr = term (("+" | "-") term)*
  term = factor (("*" | "/") factor)*
  factor = number | "(" expr ")"
  number = ~
```

--------------------------------

### Rule Declaration with Description

Source: https://github.com/ohmjs/ohm/blob/main/doc/syntax-reference.md

Example of a rule declaration with a descriptive comment for better error messages.

```ohm
ident (an identifier)
  = ~keyword name
```

--------------------------------

### Accessing Operations and Attributes

Source: https://github.com/ohmjs/ohm/blob/main/doc/api-reference.md

Example of how to access operations and attributes from a semantics instance applied to a MatchResult.

```javascript
mySemantics(matchResult).prettyPrint()
```

```javascript
mySemantics(matchResult).value
```

--------------------------------

### Ohm-Viz Initialization and Configuration

Source: https://github.com/ohmjs/ohm/blob/main/packages/memoviz-demo/index.html

This snippet shows how to initialize Ohm-Viz with specific configurations and data.

```javascript
const ohmViz = new OhmViz({
  container: document.getElementById('viz-container'),
  data: [
    { id: 0, parent: null, label: 'Root' },
    { id: 1, parent: 0, label: 'Node 1' },
    { id: 2, parent: 0, label: 'Node 2' },
    { id: 3, parent: 1, label: 'Node 1.1' },
    { id: 4, parent: 1, label: 'Node 1.2' },
    { id: 5, parent: 2, label: 'Node 2.1' },
    { id: 6, parent: 2, label: 'Node 2.2' },
  ],
  layout: 'tree',
  nodeLabel: 'label',
  nodeId: 'id',
  nodeParent: 'parent',
  linkType: 'curve',
  onNodeClick: (node) => {
    console.log('Node clicked:', node);
  },
});
```

--------------------------------

### Building the development Ohm.js Docker image locally

Source: https://github.com/ohmjs/ohm/blob/main/doc/docker.md

Command to build the development Docker image, which includes the full source tree and dev dependencies.

```sh
TARGET=build docker compose -f docker/docker-compose.yml build
```

--------------------------------

### Inline Rule Declaration

Source: https://github.com/ohmjs/ohm/blob/main/doc/syntax-reference.md

Example of an inline rule declaration using '--' followed by a case name.

```ohm
AddExp = AddExp_plus
       | MulExp
AddExp_plus = AddExp "+" MulExp
```

--------------------------------

### Text trace example

Source: https://github.com/ohmjs/ohm/blob/main/README.md

This snippet displays the output of the `trace()` method for a simple grammar, illustrating the parser's decision-making process when matching input.

```plaintext
ab         ✓ start ⇒  "ab"
ab           ✓ letter+ ⇒  "ab"
ab             ✓ letter ⇒  "a"
ab                 ✓ lower ⇒  "a"
ab                   ✓ Unicode [Ll] character ⇒  "a"
b              ✓ letter ⇒  "b"
b                  ✓ lower ⇒  "b"
b                    ✓ Unicode [Ll] character ⇒  "b"
               ✗ letter
                   ✗ lower
                     ✗ Unicode [Ll] character
                   ✗ upper
                     ✗ Unicode [Lu] character
                   ✗ unicodeLtmo
                     ✗ Unicode [Ltmo] character
           ✓ end ⇒  ""
```

--------------------------------

### Ohm-Viz Initialization and Configuration

Source: https://github.com/ohmjs/ohm/blob/main/packages/memoviz-demo/index.html

This snippet shows how to initialize Ohm-Viz with a grammar and configure its display options.

```javascript
const ohm = require("ohm-js");

const grammar = ohm.grammar(`
  G {
    start = expr
    expr = term (op expr)?
    term = "(" expr ")" | number
    op = "+" | "-"
    number = nonZeroDigit digit*
    nonZeroDigit = "1".."9"
    digit = "0".."9"
  }
`);

const viz = require("../src/index");

const display = viz.display(grammar, {
  // options for the visualization
  // e.g., showGrammar: true,
  //       showParseTree: true,
  //       showSemantics: true,
  //       showActions: true,
});

document.body.appendChild(display);
```

--------------------------------

### Ohm-Viz with Different Layouts

Source: https://github.com/ohmjs/ohm/blob/main/packages/memoviz-demo/index.html

Shows how to switch between different layout algorithms.

```javascript
ohmViz.setLayout('force'); // or 'tree', 'radial', etc.
```

--------------------------------

### Open Sequence Pattern

Source: https://github.com/ohmjs/ohm/blob/main/packages/lang-python/python-peg-grammar.txt

Handles sequences that might start with a pattern and continue with more patterns, separated by commas.

```python-peg
open_sequence_pattern[asdl_seq*]:
    | pattern=maybe_star_pattern ',' patterns=maybe_sequence_pattern? {
        _PyPegen_seq_insert_in_front(p, pattern, patterns) }
```