115 lines
3.3 KiB
Rust
115 lines
3.3 KiB
Rust
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
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pub enum IndentType {
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Spaces,
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Tabs,
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}
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#[derive(Debug, Clone)]
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pub struct IndentOptions {
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width: usize,
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indent_string: String,
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split_line_attributes: bool,
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}
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impl IndentOptions {
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pub fn new(typ: IndentType, width: usize, split_line_attributes: bool) -> Self {
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assert_ne!(width, 0, "Cannot have an indent width of 0");
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Self {
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width,
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indent_string: match typ {
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IndentType::Tabs => "\t".into(),
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IndentType::Spaces => " ".repeat(width),
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},
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split_line_attributes,
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}
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}
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/// Gets a string containing one indent worth of whitespace
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pub fn indent_str(&self) -> &str {
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&self.indent_string
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}
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/// Computes the line length in characters, counting tabs as the indent width.
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pub fn line_length(&self, line: &str) -> usize {
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line.chars()
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.map(|ch| if ch == '\t' { self.width } else { 1 })
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.sum()
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}
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/// Estimates how many times the line has been indented.
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pub fn count_indents(&self, mut line: &str) -> usize {
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let mut indent = 0;
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while !line.is_empty() {
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// Try to count tabs
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let num_tabs = line.chars().take_while(|ch| *ch == '\t').count();
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if num_tabs > 0 {
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indent += num_tabs;
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line = &line[num_tabs..];
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continue;
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}
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// Try to count spaces
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let num_spaces = line.chars().take_while(|ch| *ch == ' ').count();
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if num_spaces >= self.width {
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// Intentionally floor here to take only the amount of space that matches an indent
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let num_space_indents = num_spaces / self.width;
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indent += num_space_indents;
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line = &line[num_space_indents * self.width..];
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continue;
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}
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// Line starts with either non-indent characters or an unevent amount of spaces,
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// so no more indent remains.
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break;
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}
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indent
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}
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pub fn split_line_attributes(&self) -> bool {
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self.split_line_attributes
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}
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}
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impl Default for IndentOptions {
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fn default() -> Self {
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Self::new(IndentType::Spaces, 4, false)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn count_indents() {
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assert_eq!(
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IndentOptions::new(IndentType::Spaces, 4, false).count_indents("no indentation here!"),
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0
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);
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assert_eq!(
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IndentOptions::new(IndentType::Spaces, 4, false).count_indents(" v += 2"),
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1
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);
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assert_eq!(
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IndentOptions::new(IndentType::Spaces, 4, false).count_indents(" v += 2"),
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2
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);
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assert_eq!(
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IndentOptions::new(IndentType::Spaces, 4, false).count_indents(" v += 2"),
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2
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);
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assert_eq!(
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IndentOptions::new(IndentType::Spaces, 4, false).count_indents("\t\tv += 2"),
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2
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);
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assert_eq!(
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IndentOptions::new(IndentType::Spaces, 4, false).count_indents("\t\t v += 2"),
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2
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);
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assert_eq!(
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IndentOptions::new(IndentType::Spaces, 2, false).count_indents(" v += 2"),
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2
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);
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}
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}
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