yeanpypa.InputReader

Module yeanpypa :: Class InputReader

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Class InputReader

The InputReader serves as an abstraction to read chars from a string with a state. The reader provides tools to save the current reading position and a stack to set checkpoints where to return to later.

Method Summary
	`__init__(self, string, ignore_white)` Create this reader with the given string.
	`checkPoint(self)` Set a checkpoint in the reader.
	`deleteCheckpoint(self)` Delete the newest checkpoint without rolling back.
	`fullyConsumed(self)` Return whether the string was fully consumed
	`getChar(self)` Get a single character from the string.
	`getIgnoreState(self)` Return whether the reader is set to ignore whitespaces.
	`getPos(self)` Return the current position of this reader
	`getString(self, length)` Get a substring of the string from this reader and advance the reader's position.
	`rollback(self)` Rollback the parser to the last checkpoint set.
	`setIgnoreState(self, state)` Set the ignore state of the reader.
	`skipWhite(self)` Function to skip the whitespace characters from the current position on.

Method Details

init(self, string, ignore_white)
(Constructor)

Create this reader with the given string.

Parameters:: string - The string the reader reads from.
(type=str); ignore_white - Whether to ignore whitespaces or not.
(type=boolean)

checkPoint(self)

Set a checkpoint in the reader. A checkpoint is kind of like a safety net where the parser can return to later if parsin failed at any later point in the string. The checkpoints are managed in a stack-like fashion: the parser can always return to the last checkpoint set.

deleteCheckpoint(self)

Delete the newest checkpoint without rolling back. If a rules sucessfully matches, it deletes the previously saved checkpoint to clean up the parser stack

fullyConsumed(self)

Return whether the string was fully consumed

Returns:: True if the string was read to the last byte, False otherwise

getChar(self)

Get a single character from the string. This methdo returns the next character of the string. If ignore_whitespace is True, this will be the next non-whitespace character.

Returns:: The next character of the string.

getIgnoreState(self)

Return whether the reader is set to ignore whitespaces.

Returns:: True if the reader currently ignores whitespaces, False otherwise.

getPos(self)

Return the current position of this reader

Returns:: the current position of the reader in the string

getString(self, length)

Get a substring of the string from this reader and advance the reader's position. This method returns the current substring of the reader with the given length. Note that even if ignore_whitespace is True, the string will return any containing whitespaces.

Parameters:: length - The length of the string to return
(type=int)

Returns:: A substring of the given length.

rollback(self)

Rollback the parser to the last checkpoint set. This is called by the rules internally whenever parsing fails and a rollback is necessary.

setIgnoreState(self, state)

Set the ignore state of the reader. This call tells the reader whether it should ignore whitespaces or not.

Parameters:: state - True to ignore whitespace, False to return them
(type=boolean)

skipWhite(self)

Function to skip the whitespace characters from the current position on.

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