parser-pda 0.1.5

This crate provides a demo of using [fi_night] crate for implementation of a simple parser capable of indexing nested bracketed segments of text. The parser distinguishes sentences separated by '.' and [bracketed] text segments. The automaton implementation can be seen in modules parser_pda.rs and parser_nondet_pda.rs which implement two versions providing the same functionality.

Here is an example:

use parser_pda::{create_parser_pda_instance} ;
use parser_pda::parser_pda::{LittleParser, LittleParserTrait, LittleParserStates::*, LittleParserSignals::*,
LITTLE_PARSER_GEN_CODE};

fn main() {
let mut parser = create_parser_pda_instance();

fsm_code_to_file("parser_automaton", "target/fsm", LITTLE_PARSER_GEN_CODE);

let text = "Fif[teen] men on a dead man's [[chest]]. []]Yo [[ho [[ho. And [the [bottle] ]of [[[RUM]]] ";

parser.start();

for ch in text.chars() {
match ch {
'[' => parser.next(&LeftBracket),
']' => parser.next(&RightBracket),
'.' => parser.next(&EndOfSentence),
ch @ _ => parser.next(&Letter(ch)),
}
}
parser.stop();   

display_output(&text, &mut parser);

fn display_output(text: &str, parser: &mut LittleParser) {
use substring::Substring;
println!("input: {}\n", text);
while let Some(seg) = parser.data_mut().segments.pop() {
let tabbed = "\t".repeat(seg.rank);

println!("{} {}[{} {}) -> {}", tabbed, seg.tp, seg.seg.0, seg.seg.1,
text.substring(seg.seg.0, seg.seg.1));
}   
}
}

use std::fs::{File, create_dir};
use std::io::{Seek, Write};

fn fsm_code_to_file(fname: &str, path: &str, gen_code: &str) {

let _ = create_dir(path);

File::create(&format!("{}/{}.rs", path, fname))
.and_then(|mut file| {
file.seek(std::io::SeekFrom::End(0))?;
file.write_all(gen_code.to_string().as_bytes())?;
file.flush()
});
}

The code running stores the rust code of the automaton under /target/fsm/parser_automaton.rs and emits the following output:

input: Fif[teen] men on a dead man's [[chest]]. []]Yo [[ho [[ho. And [the [bottle] ]of [[[RUM]]] 

Sentence[0 39) -> Fif[teen] men on a dead man's [[chest]]
Plain[0 30) -> Fif[teen] men on a dead man's 
Plain[0 3) -> Fif
Bracketed[4 8) -> teen
Bracketed[31 38) -> [chest]
Bracketed[32 37) -> chest
InvalidSentence[40 56) ->  []]Yo [[ho [[ho
Plain[40 43) ->  []
Plain[40 41) ->  
Bracketed[42 42) -> 
UnbalancedRightSth[43 56) -> ]Yo [[ho [[ho
Tail[57 90) ->  And [the [bottle] ]of [[[RUM]]] 
Plain[57 80) ->  And [the [bottle] ]of 
Plain[57 62) ->  And 
Bracketed[63 76) -> the [bottle] 
Bracketed[68 74) -> bottle
Bracketed[81 88) -> [[RUM]]
Bracketed[82 87) -> [RUM]
Bracketed[83 86) -> RUM