lalrpop 0.23.0

convenient LR(1) parser generator
Documentation 
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use crate::grammar::repr::*;
use crate::test_util::expect_debug;
use crate::tls::Tls;
use string_cache::DefaultAtom as Atom;

use super::{Example, ExampleSymbol, Reduction};

fn nt(t: &str) -> NonterminalString {
    NonterminalString(Atom::from(t))
}

fn term(t: &str) -> TerminalString {
    TerminalString::quoted(Atom::from(t))
}

macro_rules! sym {
    (ε) => {
        ExampleSymbol::Epsilon
    };
    ($t:ident) => {
        ExampleSymbol::Symbol(Symbol::Nonterminal(nt(stringify!($t))))
    };
}

macro_rules! syms {
    ($($t:tt),*) => {
        vec![$(sym!($t)),*]
    }
}

//  01234567890123456789012
//  A1   B2  C3  D4 E5 F6
//  |             |     |
//  +-LongLabel22-+     |
//  |                   |
//  +-Label-------------+
fn long_label_1_example() -> Example {
    Example {
        symbols: syms!(A1, B2, C3, D4, E5, F6),
        cursor: 5,
        reductions: vec![
            Reduction {
                start: 0,
                end: 4,
                nonterminal: nt("LongLabel22"),
            },
            Reduction {
                start: 0,
                end: 6,
                nonterminal: nt("Label"),
            },
        ],
    }
}

#[test]
fn long_label_1_positions() {
    let _tls = Tls::test();
    let example = long_label_1_example();
    let lengths = example.lengths();
    let positions = example.positions(&lengths);
    assert_eq!(positions, vec![0, 5, 9, 13, 16, 19, 22]);
}

#[test]
fn long_label_1_strings() {
    let _tls = Tls::test();
    let strings = long_label_1_example().paint_unstyled();
    expect_debug(
        strings,
        r#"
[
    "  A1   B2  C3  D4 E5 F6",
    "  ├─LongLabel22─┘     │",
    "  └─Label─────────────┘"
]
"#
        .trim(),
    );
}

// Example with some empty sequences and
// other edge cases.
//
//  012345678901234567890123456789012345
//         A1  B2  C3 D4 E5       F6
//  |   |           |       |   | |   |
//  +-X-+           |       |   | |   |
//  |               |       |   | |   |
//  +-MegaLongLabel-+       |   | |   |
//                          |   | |   |
//                          +-Y-+ |   |
//                                |   |
//                                +-Z-+
fn empty_labels_example() -> Example {
    Example {
        //             0 1  2  3  4  5  6 7
        symbols: syms!(ε, A1, B2, C3, D4, E5, ε, F6),
        cursor: 5,
        reductions: vec![
            Reduction {
                start: 0,
                end: 1,
                nonterminal: nt("X"),
            },
            Reduction {
                start: 0,
                end: 4,
                nonterminal: nt("MegaLongLabel"),
            },
            Reduction {
                start: 6,
                end: 7,
                nonterminal: nt("Y"),
            },
            Reduction {
                start: 7,
                end: 8,
                nonterminal: nt("Z"),
            },
        ],
    }
}

#[test]
fn empty_labels_positions() {
    let _tls = Tls::test();
    let example = empty_labels_example();
    let lengths = example.lengths();
    let positions = example.positions(&lengths);
    //                            A1 B2  C3  D4  E5      F6
    assert_eq!(positions, vec![0, 7, 11, 15, 18, 21, 24, 30, 36]);
}

#[test]
fn empty_labels_strings() {
    let _tls = Tls::test();
    let strings = empty_labels_example().paint_unstyled();
    expect_debug(
        strings,
        r#"
[
    "  ╷    ╷ A1  B2  C3 D4 E5 ╷   ╷ F6  ╷",
    "  ├─X──┘          │       │   │ │   │",
    "  └─MegaLongLabel─┘       │   │ │   │",
    "                          └─Y─┘ │   │",
    "                                └─Z─┘"
]
"#
        .trim(),
    );
}

// _return_      _A_ Expression _B_
// |            |                  |
// +-ExprAtom---+                  |
// |            |                  |
// +-ExprSuffix-+                  |
// |                               |
// +-ExprSuffix--------------------+
fn single_token_example() -> Example {
    Example {
        //             0 1  2  3  4  5  6 7
        symbols: syms!(_return_, _A_, Expression, _B_),
        cursor: 5,
        reductions: vec![
            Reduction {
                start: 0,
                end: 1,
                nonterminal: nt("ExprAtom"),
            },
            Reduction {
                start: 0,
                end: 1,
                nonterminal: nt("ExprSuffix"),
            },
            Reduction {
                start: 0,
                end: 4,
                nonterminal: nt("ExprSuffix"),
            },
        ],
    }
}

#[test]
fn single_token_strings() {
    let _tls = Tls::test();
    let strings = single_token_example().paint_unstyled();
    expect_debug(
        strings,
        r#"
[
    "  _return_     ╷ _A_ Expression _B_",
    "  ├─ExprAtom───┤                  │",
    "  ├─ExprSuffix─┘                  │",
    "  └─ExprSuffix────────────────────┘"
]
"#
        .trim(),
    );
}