Struct lib_ruby_parser::ParserOptions[−][src]

pub struct ParserOptions {
    pub buffer_name: String,
    pub debug: Type,
    pub decoder: Option<Decoder>,
    pub token_rewriter: Option<TokenRewriter>,
    pub record_tokens: bool,
}

Expand description

Configuration of the parser

Fields

buffer_name: String

Name of the buffer. Used in all diagnostic messages

debug: Type

Controls which debug information is printed during parsing

Can be:

lib_ruby_parser::debug_level::None
lib_ruby_parser::debug_level::Parser
lib_ruby_parser::debug_level::Lexer
lib_ruby_parser::debug_level::Buffer
or a combination of them (like Lexer | Buffer, this value is just a bitmask)

decoder: Option<Decoder>

Custom decoder that can be used if the source is encoded in unknown encoding. Only UTF-8 and ASCII-8BIT/BINARY are supported out of the box.

Example

use lib_ruby_parser::source::{Decoder, DecoderResult, InputError};
use lib_ruby_parser::{debug_level, Parser, ParserOptions, ParserResult};

fn decode(encoding: String, input: Vec<u8>) -> DecoderResult {
    if "US-ASCII" == encoding.to_uppercase() {
        // reencode and return Ok(result)
        return DecoderResult::Ok(b"# encoding: us-ascii\ndecoded".to_vec().into());
    }
    DecoderResult::Err(InputError::DecodingError(
        "only us-ascii is supported".into(),
    ))
}

let decoder = Decoder::new(Box::new(decode));
let options = ParserOptions {
    decoder: Some(decoder),
    debug: debug_level::PARSER,
    ..Default::default()
};
let parser = Parser::new(b"# encoding: us-ascii\n3 + 3".to_vec(), options);
let ParserResult { ast, input, .. } = parser.do_parse();

assert_eq!(
    ast.unwrap().expression().source(&input).unwrap(),
    "decoded".to_string()
)

token_rewriter: Option<TokenRewriter>

Optional token rewriter, see TokenRewriter API

Example

use lib_ruby_parser::{
    nodes::*,
    source::token_rewriter::*,
    Bytes, Node, Parser, ParserOptions, ParserResult, Token,
};
fn rewrite_foo_to_bar(mut token: Box<Token>, input: &[u8]) -> TokenRewriterResult {
    // simply rewrite all tokens "foo" to "bar"
    if token.to_string_lossy() == "foo" {
        token.set_token_value(Bytes::new(b"bar".to_vec()));
    }

    // return token + keep it + keep lexer's state
    TokenRewriterResult {
        rewritten_token: token,
        token_action: RewriteAction::Keep,
        lex_state_action: LexStateAction::Keep,
    }
}
let token_rewriter = TokenRewriter::new(Box::new(rewrite_foo_to_bar));
let options = ParserOptions {
    token_rewriter: Some(token_rewriter),
    ..Default::default()
};
let ParserResult { ast, .. } = Parser::new(b"foo = 1".to_vec(), options).do_parse();

let ast = ast.unwrap();

let lvar_name = match &*ast {
    Node::Lvasgn(Lvasgn { name, .. }) => name,
    other => panic!("expected lvasgn node, got {:?}", other),
};
assert_eq!(*lvar_name, String::from("bar"));

record_tokens: bool

When set to true Parser records tokens. When set to false ParserResult.tokens is guaranteed to be empty. If you don’t need tokens better set it to false to speed up parsing.