README

This is a parser/printer for a subset of PHP focused on data. (It serves a role similar to a full-service YAML library - except with *.php data-files.) Key features:

• Allows array values and scalar values (string, int, bool, etc).
• Allows comments for the overall document and for individual items in the tree.
• Allows tagged-values (a.k.a. factory-functions) which look like global or static method-calls.
• Allows deferred construction (fn() => [...data...])
• Prohibits objects, loops, math, concatenation, includes, custom functions, etc.

Examples: Data documents

A basic document looks like this:

<?php
return [
  // First item is a string.
  'key_1' => 'value_1',

  // Second item is an array of floats.
  'key_2' => [2.1, 2.2, 2.3],

  // Third item is an array.
  'key_3' => [
    'part_a' => 'Apple',
    'part_b' => 'Banana',
  ]
];

This next example is similar, but it adds a "tagged value" or "factory function" called MyHelper::translate():

<?php
use MyHelper as H;

return [
  'id' => 1234,
  'name' => 'greeter',
  'label' => H::translate('Hello World'),
];

Note that H::translate('Hello world') takes exactly one parameter. It only supports a subset of PHP function-calls -- i.e. with one parameter; with global-function or static-method. (H::translate is less like an open-ended function-call and more like a tag that describes Hello world.)

The same concept can be applied to generate objects/records, as long as there is exactly one parameter:

use MyHelper as H;

return H::record([
  'id' => 1234,
  'name' => 'greeter',
  'label' => H::translate('Hello World'),
]);

Value resolution may be defererd, as in:

use MyHelper as H;

return H::record([
  'id' => 1234,
  'name' => 'greeter',
  'label' => fn() => H::translate('Hello World'),
]);

Examples: File manipulation

Generate a new *.php data file. Populate it with importData($array):

$doc = PhpArrayDocument::create();
$doc->getRoot()->importData([
  'id' => 1234,
  'name' => 'greeting',
  'label' => ScalarNode::create('Hello World')->setFactory('E::ts'),
]);

$file = 'my.data.php';
file_put_contents($file, (new Printer())->print($doc));

Read an existing file. Update individual items in the parse-tree. Save the updated file.

$file = 'my.data.php';
$doc = (new Parser())->parse(file_get_contents($file));

$root = $doc->getRoot();
$root['id'] = ScalarNode::create(100);
$root['name'] = ScalarNode::create('greeting');
$root['label'] = ScalarNode::create('Hello World')->setFactory('E::ts');

file_put_contents($file, (new Printer())->print($doc));

Update an existing file. Do a global search (walkNodes()). Find references to OldHelper::method and replace them with NewHelper::method.

$file = 'my.data.php';
$doc = (new Parser())->parse(file_get_contents($file));

foreach ($doc->getRoot()->walkNodes() as $node) {
  if ($node->getFactory() === 'OldHelper::method') {
    $node->setFactory('NewHelper::method');
  }
}

file_put_contents($file, (new Printer())->print($doc));

Cheatsheet

Some commands to help with debugging:

## Parse and re-print an improvised PHP snippet
echo '<?php return [1,2,3];' | ./scripts/reprint.php

## Tokenize an improvised PHP snippet
echo '<?php return [1,2,3];' | ./scripts/tokenize.php

## Parse an improvised PHP snippet
echo '<?php return [1,2,3];' | ./scripts/parse.php

## Parse and re-print a PHP file
cat examples/simple-array-7.4.php | ./scripts/reprint.php | less

## Tokenize a PHP file
cat examples/simple-array-7.4.php | ./scripts/tokenize.php | less

## Parse a PHP file
cat examples/simple-array-7.4.php | ./scripts/parse.php | less

Model

• Basic Concepts
  • Substance: Each "PHP array document" contains a tree of arrays and scalars.
  • Metadata: Individual values may be annotated with comments and/or factory-functions (such as ts(...)).
  • Evaluation: If you include or require the PHP document directly, you will literally get arrays and scalars.
  • Read/Write: If you need to programmatically inspect or update the content, then the PhpArrayDocument aims to help.
• Verbs
  • Parse: Read the PHP document as an instance of PhpArrayDocument
  • Print: Render PhpArrayDocument as a string (<?php return [...])
  • Import Data: Add basic PHP array data to a PhpArrayDocument (without any metadata/comments/factory-functions)
  • Export Data: Grab the PHP (discarding any metadata/comments/factory-functions)
  • Walk Nodes: Visit all the nodes in the tree. Useful for general filtering/searching/replacing.
• Classes
  • Data-Focused Classes
    • PhpArrayDocument: This captures the overall *.php file, including any top-level elements (use or docblocks) and the root array.
    • ArrayNode (extends BaseNode): An element in the tree that corresponds to array()
    • ArrayItemNode (extends BaseNode): A key-value pair that exists within an array()
    • ScalarNode (extends BaseNode): An atomic value that lives inside an array.
  • Functionality-Focused Classes
    • Parser: Take a raw string. Generate a PhpArrayDocument.
    • Printer: Take a PhpArrayDocument. Generate a string