lalrpop 0.12.2

convenient LR(1) parser generator
Documentation 
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use intern::intern;
use grammar::repr::*;
use test_util::expect_debug;
use tls::Tls;

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

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

fn term(t: &str) -> TerminalString {
    TerminalString::Literal(TerminalLiteral::Quoted(intern(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());
}