1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81

use crate::rail_machine::{RailDef, Stack};

pub fn builtins() -> Vec<RailDef<'static>> {
    vec![
        RailDef::on_state("upcase", &["string"], &["string"], |state| {
            state.update_stack(|stack| {
                let (s, stack) = stack.pop_string("upcase");
                stack.push_string(s.to_uppercase())
            })
        }),
        RailDef::on_state("downcase", &["string"], &["string"], |state| {
            state.update_stack(|stack| {
                let (s, stack) = stack.pop_string("downcase");
                stack.push_string(s.to_lowercase())
            })
        }),
        RailDef::on_state("trim", &["string"], &["string"], |state| {
            state.update_stack(|stack| {
                let (s, stack) = stack.pop_string("trim");
                stack.push_string(s.trim().to_string())
            })
        }),
        string_splitter("words", " "),
        string_joiner("unwords", " "),
        string_splitter("chars", ""),
        string_splitter("lines", "\n"),
        string_joiner("unlines", "\n"),
        RailDef::on_state("split", &["string", "string"], &["quot"], |state| {
            state.update_stack(|stack| {
                let (delimiter, stack) = stack.pop_string("split");
                let (s, stack) = stack.pop_string("split");
                stack.push_quotation(split(s, &delimiter))
            })
        }),
        RailDef::on_state("join", &["quot", "string"], &["string"], |state| {
            state.update_stack(|stack| {
                let (delimiter, stack) = stack.pop_string("join");
                let (quot, stack) = stack.pop_quotation("join");
                stack.push_string(join("join", quot, &delimiter))
            })
        }),
    ]
}

fn string_splitter<'a>(name: &'a str, delimiter: &'a str) -> RailDef<'a> {
    RailDef::on_state(name, &["string"], &["quot"], move |state| {
        state.update_stack(|stack| {
            let (s, stack) = stack.pop_string(name);
            stack.push_quotation(split(s, delimiter))
        })
    })
}

fn split(s: String, delimiter: &str) -> Stack {
    let mut words = Stack::new();
    for s in s.split(delimiter) {
        words = words.push_str(s);
    }
    words
}

fn string_joiner<'a>(name: &'a str, delimiter: &'a str) -> RailDef<'a> {
    RailDef::on_state(name, &["string"], &["quot"], move |state| {
        state.update_stack(|stack| {
            let (quot, stack) = stack.pop_quotation(name);
            stack.push_string(join(name, quot, delimiter))
        })
    })
}

fn join(context: &str, words: Stack, delimiter: &str) -> String {
    let mut s = vec![];
    let mut words = words;
    while !words.is_empty() {
        let (part, new_words) = words.pop_string(context);
        s.push(part);
        words = new_words
    }
    s.reverse();
    s.join(delimiter)
}