parser_options.md

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parser::options

options plain struct object can be provided to a parser to change its default behavior.

attributes

bool binarize;

If binarize is true parser applies binarization to ensure every forest node has at most 2 or less children nodes.

Binarization splits rules with more than two children nodes into multiple rules by adding new temporary production rules.

This adds additional intermediate __temp symbols into a resulting forest. Use bool remove_binarization(graph&); to remove these symbols.

Default value is false.

bool incr_gen_forest;

If incr_gen_forest is true parser builds forests incrementally as soon as any item is completed.

Default value is false.

terminal_codec<C, T> codec;

Bundled decoder and encoder for converting between input character type C and terminal type T. See recoders for function signatures and built-in UTF-8 converters.

• codec.decode - decoder (decoder_type), default empty (no decoder)
• codec.encode - encoder (encoder_type), default empty (no encoder)

For char input and char32_t terminals, idni::default_parser_options<C, T>() pre-wires UTF-8 recoders.

constructor

parser<C, T>::options();

example

parser<char, char32_t>::options opts;

opts.binarize = true;
opts.codec.decode = utf8_to_u32_conv; // lib provided utf8 to u32
opts.codec.encode = u32_to_utf8_conv; // lib provided u32 to utf8