oak-perl 0.0.11

Perl scripting language parser with support for text processing, system administration, and modern Perl features.
Documentation 
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#![doc = include_str!("readme.md")]
/// Local definition of highlight kinds.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum HighlightKind {
    /// Keyword.
    Keyword,
    /// String.
    String,
    /// Number.
    Number,
    /// Comment.
    Comment,
    /// Identifier.
    Identifier,
}

/// Highlighter trait.
pub trait Highlighter {
    /// Highlights the given text and returns a list of (start, end, kind) tuples.
    fn highlight(&self, text: &str) -> Vec<(usize, usize, HighlightKind)>;
}

/// Perl syntax highlighter.
pub struct PerlHighlighter {
    /// Whether to use the parser for highlighting.
    pub use_parser: bool,
}

impl Default for PerlHighlighter {
    fn default() -> Self {
        Self { use_parser: false }
    }
}

impl PerlHighlighter {
    /// Creates a new instance of `PerlHighlighter`.
    pub fn new() -> Self {
        Self::default()
    }

    /// Creates a new instance of `PerlHighlighter` that uses the parser.
    pub fn with_parser() -> Self {
        Self { use_parser: true }
    }

    fn highlight_keywords(&self, text: &str) -> Vec<(usize, usize, HighlightKind)> {
        let mut highlights = Vec::new();
        let keywords = [
            "if", "else", "elsif", "unless", "while", "until", "for", "foreach", "next", "last", "redo", "sub", "my", "our", "local", "use", "require", "package", "return", "eval", "die", "warn", "print", "printf", "say", "shift", "unshift", "push",
            "pop", "split", "join", "map", "grep", "sort", "reverse", "keys", "values", "each", "delete", "exists", "defined", "undef", "scalar", "array", "hash", "ref", "bless", "tie", "untie", "package", "strict", "warnings",
        ];

        for keyword in &keywords {
            let mut start = 0;
            while let Some(pos) = text[start..].find(keyword) {
                let absolute_pos = start + pos;
                let end_pos = absolute_pos + keyword.len();

                let is_word_boundary_before = absolute_pos == 0 || !text.chars().nth(absolute_pos - 1).unwrap_or(' ').is_alphanumeric();
                let is_word_boundary_after = end_pos >= text.len() || !text.chars().nth(end_pos).unwrap_or(' ').is_alphanumeric();

                if is_word_boundary_before && is_word_boundary_after {
                    highlights.push((absolute_pos, end_pos, HighlightKind::Keyword));
                }

                start = absolute_pos + 1;
            }
        }

        highlights
    }
}

impl Highlighter for PerlHighlighter {
    fn highlight(&self, text: &str) -> Vec<(usize, usize, HighlightKind)> {
        let mut highlights = self.highlight_keywords(text);
        highlights.sort_by_key(|h| h.0);
        highlights
    }
}