Struct design_pattern_examples_rust::state::state_context::InputOutput

struct InputOutput {
    input_text: Vec<char>,
    text_index: usize,
    output_text: String,
}

Represents an input string and an output string, along with an index into the input string. This is used for running the individual characters of the input through the finite state machine to produce filtered output.

(Normally, the input and output would appear on the StateContext struct, however, there was a circular reference between the IStateContext trait and the IStateBehavior::go_next() method, resulting in an error where a mutable borrow was occurring on an already mutable borrow. Only way around this was to separate the input/output stuff from the context stuff.)

Fields

input_text: Vec<char>

Text to be filtered. The given text is converted to a vector so it can be indexed, allowing us to easily detect end of string.

text_index: usize

Index into the input text.

output_text: String

The output string that accumulates the filtered text.

Implementations

impl InputOutput

fn new(input_text: &str) -> InputOutput

Constructor

Parameters

• input_text

  The text to be filtered.

Returns

Returns a new instance of the InputOutput struct.

Trait Implementations

impl IStateContext for InputOutput

fn get_next_character(&mut self) -> StateChar

Get the next character from the input.

fn output_character(&mut self, character: StateChar)

Write the character to the context. This is how the parser accumulates the filtered text.