Function parse_multiline

cranelift/srcgen/src/lib.rs:265–315

Given a multi-line string, split it into a sequence of lines after stripping a common indentation. This is useful for strings defined with doc strings.

(s: &str)

/// stripping a common indentation. This is useful for strings defined with
/// doc strings.
fn parse_multiline(s: &str) -> Vec<String> {
    // Convert tabs into spaces.
    let expanded_tab = format!("{:-1$}", " ", SHIFTWIDTH);
    let lines: Vec<String> = s.lines().map(|l| l.replace('\t', &expanded_tab)).collect();

    // Determine minimum indentation, ignoring the first line and empty lines.
    let indent = lines
        .iter()
        .skip(1)
        .filter(|l| !l.trim().is_empty())
        .map(|l| l.len() - l.trim_start().len())
        .min();

    // Strip off leading blank lines.
    let mut lines_iter = lines.iter().skip_while(|l| l.is_empty());
    let mut trimmed = Vec::with_capacity(lines.len());

    // Remove indentation (first line is special)
    if let Some(s) = lines_iter.next().map(|l| l.trim()).map(|l| l.to_string()) {
        trimmed.push(s);
    }

    // Remove trailing whitespace from other lines.
    let mut other_lines = if let Some(indent) = indent {
        // Note that empty lines may have fewer than `indent` chars.
        lines_iter
            .map(|l| &l[cmp::min(indent, l.len())..])
            .map(|l| l.trim_end())
            .map(|l| l.to_string())
            .collect::<Vec<_>>()
    } else {
        lines_iter
            .map(|l| l.trim_end())
            .map(|l| l.to_string())
            .collect::<Vec<_>>()
    };

    trimmed.append(&mut other_lines);

    // Strip off trailing blank lines.
    while let Some(s) = trimmed.pop() {
        if s.is_empty() {
            continue;
        } else {
            trimmed.push(s);
            break;
        }
    }

    trimmed
}

/// Match formatting class.
///