Initial commit for fern

src/prompt/readline.rs

@@ -0,0 +1,90 @@
+use rustyline::{completion::{Completer, FilenameCompleter}, highlight::Highlighter, hint::{Hint, Hinter}, history::{History, SearchDirection}, validate::{ValidationResult, Validator}, Helper};
+
+use crate::prelude::*;
+
+pub struct SynHelper<'a> {
+	file_comp: FilenameCompleter,
+	pub shenv: &'a mut ShEnv,
+	pub commands: Vec<String>
+}
+
+impl<'a> Helper for SynHelper<'a> {}
+
+impl<'a> SynHelper<'a> {
+	pub fn new(shenv: &'a mut ShEnv) -> Self {
+		Self {
+			file_comp: FilenameCompleter::new(),
+			shenv,
+			commands: vec![]
+		}
+	}
+
+	pub fn hist_search(&self, term: &str, hist: &dyn History) -> Option<String> {
+		let limit = hist.len();
+		let mut latest_match = None;
+		for i in 0..limit {
+			if let Some(hist_entry) = hist.get(i, SearchDirection::Forward).ok()? {
+				if hist_entry.entry.starts_with(term) {
+					latest_match = Some(hist_entry.entry.into_owned())
+				}
+			}
+		}
+		latest_match
+	}
+}
+
+impl<'a> Validator for SynHelper<'a> {
+	fn validate(&self, ctx: &mut rustyline::validate::ValidationContext) -> rustyline::Result<rustyline::validate::ValidationResult> {
+		Ok(ValidationResult::Valid(None))
+	}
+}
+
+
+impl<'a> Completer for SynHelper<'a> {
+	type Candidate = String;
+	fn complete( &self, line: &str, pos: usize, ctx: &rustyline::Context<'_>,) -> rustyline::Result<(usize, Vec<Self::Candidate>)> {
+		Ok((0,vec![]))
+	}
+}
+
+pub struct SynHint {
+	text: String,
+	styled: String
+}
+
+impl SynHint {
+	pub fn new(text: String) -> Self {
+		let styled = style_text(&text, Style::BrightBlack);
+		Self { text, styled }
+	}
+	pub fn empty() -> Self {
+		Self { text: String::new(), styled: String::new() }
+	}
+}
+
+impl Hint for SynHint {
+	fn display(&self) -> &str {
+	  &self.styled
+	}
+	fn completion(&self) -> Option<&str> {
+	  if !self.text.is_empty() {
+			Some(&self.text)
+		} else {
+			None
+		}
+	}
+}
+
+impl<'a> Hinter for SynHelper<'a> {
+	type Hint = SynHint;
+	fn hint(&self, line: &str, pos: usize, ctx: &rustyline::Context<'_>) -> Option<Self::Hint> {
+		return Some(SynHint::empty());
+		if line.is_empty() {
+			return None
+		}
+		let history = ctx.history();
+		let result = self.hist_search(line, history)?;
+		let window = result[line.len()..].to_string();
+		Some(SynHint::new(window))
+	}
+}