hcl-rs 0.19.7

HCL parser and formatter for rust with serde support
Documentation 
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
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

use super::*;

pub(super) fn evaluate_template(
    result: &mut String,
    template: &Template,
    ctx: &Context,
    prev_strip: Strip,
    next_strip: Strip,
) -> EvalResult<()> {
    let elems = template.elements();
    let len = elems.len();

    for (index, elem) in elems.iter().enumerate() {
        let (prev, next) = if index == 0 && len == 1 {
            (prev_strip, next_strip)
        } else if index == 0 {
            (prev_strip, elems[index + 1].strip())
        } else if index == len - 1 {
            (elems[index - 1].strip(), next_strip)
        } else {
            (elems[index - 1].strip(), elems[index + 1].strip())
        };

        evaluate_element(result, elem, ctx, prev, next)?;
    }

    Ok(())
}

fn evaluate_element(
    result: &mut String,
    element: &Element,
    ctx: &Context,
    prev_strip: Strip,
    next_strip: Strip,
) -> EvalResult<()> {
    match element {
        Element::Literal(literal) => {
            result.push_str(strip_literal(literal, prev_strip, next_strip));
            Ok(())
        }
        Element::Interpolation(interp) => evaluate_interpolation(result, interp, ctx),
        Element::Directive(dir) => evaluate_directive(result, dir, ctx),
    }
}

// Depending on the `StripMode`, strips off leading and trailing spaces up until the first line
// break that is encountered. The line break is stripped as well.
fn strip_literal(mut literal: &str, prev_strip: Strip, next_strip: Strip) -> &str {
    fn is_space(ch: char) -> bool {
        ch.is_whitespace() && ch != '\r' && ch != '\n'
    }

    fn trim_start(s: &str) -> &str {
        let s = s.trim_start_matches(is_space);

        s.strip_prefix("\r\n")
            .or_else(|| s.strip_prefix('\n'))
            .unwrap_or(s)
    }

    fn trim_end(s: &str) -> &str {
        let s = s.trim_end_matches(is_space);

        s.strip_suffix("\r\n")
            .or_else(|| s.strip_suffix('\n'))
            .unwrap_or(s)
    }

    if prev_strip.strip_end() {
        literal = trim_start(literal);
    }

    if next_strip.strip_start() {
        literal = trim_end(literal);
    }

    literal
}

fn evaluate_interpolation(
    result: &mut String,
    interp: &Interpolation,
    ctx: &Context,
) -> EvalResult<()> {
    let string = match interp.expr.evaluate(ctx)? {
        Value::String(string) => string,
        other => other.to_string(),
    };

    result.push_str(&string);
    Ok(())
}

fn evaluate_directive(result: &mut String, dir: &Directive, ctx: &Context) -> EvalResult<()> {
    match dir {
        Directive::If(dir) => evaluate_if_directive(result, dir, ctx),
        Directive::For(dir) => evaluate_for_directive(result, dir, ctx),
    }
}

fn evaluate_if_directive(result: &mut String, dir: &IfDirective, ctx: &Context) -> EvalResult<()> {
    if expr::evaluate_bool(&dir.cond_expr, ctx)? {
        let next_strip = if dir.false_template.is_some() {
            dir.else_strip
        } else {
            dir.endif_strip
        };
        evaluate_template(result, &dir.true_template, ctx, dir.if_strip, next_strip)?;
    } else if let Some(false_template) = &dir.false_template {
        evaluate_template(result, false_template, ctx, dir.else_strip, dir.endif_strip)?;
    }

    Ok(())
}

fn evaluate_for_directive(
    result: &mut String,
    dir: &ForDirective,
    ctx: &Context,
) -> EvalResult<()> {
    let collection = expr::Collection::from_for_directive(dir, ctx)?;

    for ctx in collection {
        evaluate_template(
            result,
            &dir.template,
            &ctx?,
            dir.for_strip,
            dir.endfor_strip,
        )?;
    }

    Ok(())
}