Implemented functions and aliases

src/expand/alias.rs

@@ -0,0 +1,75 @@
+use crate::{parse::lex::SEPARATORS, prelude::*};
+
+pub fn expand_aliases(input: &str, shenv: &mut ShEnv) -> Option<String> {
+	let mut result = input.to_string();
+	let mut expanded_aliases = Vec::new();
+	let mut found_in_iteration = true;
+
+	// Loop until no new alias expansion happens.
+	while found_in_iteration {
+		found_in_iteration = false;
+		let mut new_result = String::new();
+		let mut chars = result.chars().peekable();
+		let mut alias_cand = String::new();
+		let mut is_cmd = true;
+
+		while let Some(ch) = chars.next() {
+			match ch {
+				';' | '\n' => {
+					new_result.push(ch);
+					is_cmd = true;
+					// Consume any extra whitespace or delimiters.
+					while let Some(&next_ch) = chars.peek() {
+						if matches!(next_ch, ' ' | '\t' | ';' | '\n') {
+							new_result.push(next_ch);
+							chars.next();
+						} else {
+							break;
+						}
+					}
+				}
+				' ' | '\t' => {
+					is_cmd = false;
+					new_result.push(ch);
+				}
+				_ if is_cmd => {
+					// Accumulate token characters.
+					alias_cand.push(ch);
+					while let Some(&next_ch) = chars.peek() {
+						if matches!(next_ch, ' ' | '\t' | ';' | '\n') {
+							break;
+						} else {
+							alias_cand.push(next_ch);
+							chars.next();
+						}
+					}
+					// Check for an alias expansion.
+					if let Some(alias) = shenv.logic().get_alias(&alias_cand) {
+						// Only expand if we haven't already done so.
+						if !expanded_aliases.contains(&alias_cand) {
+							new_result.push_str(alias);
+							expanded_aliases.push(alias_cand.clone());
+							found_in_iteration = true;
+						} else {
+							new_result.push_str(&alias_cand);
+						}
+					} else {
+						new_result.push_str(&alias_cand);
+					}
+					alias_cand.clear();
+				}
+				_ => {
+					new_result.push(ch);
+				}
+			}
+		}
+		result = new_result;
+		log!(DEBUG, result);
+	}
+
+	if expanded_aliases.is_empty() {
+		None
+	} else {
+		Some(result)
+	}
+}