# Parsing Text into Joy Expressions

TODO: example…

## `joy.parser`

This module exports a single function for converting text to a joy expression as well as a single Symbol class and a single Exception type.

The Symbol string class is used by the interpreter to recognize literals by the fact that they are not Symbol objects.

A crude grammar:

    joy = term*
    term = int | float | string | '[' joy ']' | symbol

A Joy expression is a sequence of zero or more terms. A term is a literal value (integer, float, string, or Joy expression) or a function symbol. Function symbols are unquoted strings and cannot contain square brackets. Terms must be separated by blanks, which can be omitted around square brackets.

exception `joy.parser.``ParseError`

  Raised when there is a error while parsing text.

class `joy.parser.``Symbol`

  A string class that represents Joy function names.

`joy.parser.``text_to_expression`(text)

  Convert a string to a Joy expression.

  When supplied with a string this function returns a Python datastructure that represents the Joy datastructure described by the text expression. Any unbalanced square brackets will raise a ParseError.

  Parameters: | text (str) – Text to convert.
  Return type: | stack
  Raises: | ParseError – if the parse fails.

## Parser Internals

TODO: Document things like the regular expressions used for tokenizing, and the re.Scanner, etc…