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src/text/dedent.rs

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+/**
+ * Dedent a multiline string by removing common leading whitespace.
+ * 
+ * This function analyzes all non-empty lines in the input text to determine
+ * the minimum indentation level, then removes that amount of whitespace
+ * from the beginning of each line. This is useful for working with
+ * multi-line strings in code that have been indented to match the
+ * surrounding code structure.
+ * 
+ * # Arguments
+ * 
+ * * `text` - The multiline string to dedent
+ * 
+ * # Returns
+ * 
+ * * `String` - The dedented string
+ * 
+ * # Examples
+ * 
+ * ```
+ * let indented = "    line 1\n    line 2\n        line 3";
+ * let dedented = dedent(indented);
+ * assert_eq!(dedented, "line 1\nline 2\n    line 3");
+ * ```
+ * 
+ * # Notes
+ * 
+ * - Empty lines are preserved but have all leading whitespace removed
+ * - Tabs are counted as 4 spaces for indentation purposes
+ */
+pub fn dedent(text: &str) -> String {
+    let lines: Vec<&str> = text.lines().collect();
+
+    // Find the minimum indentation level (ignore empty lines)
+    let min_indent = lines.iter()
+        .filter(|line| !line.trim().is_empty())
+        .map(|line| {
+            let mut spaces = 0;
+            for c in line.chars() {
+                if c == ' ' {
+                    spaces += 1;
+                } else if c == '\t' {
+                    spaces += 4; // Count tabs as 4 spaces
+                } else {
+                    break;
+                }
+            }
+            spaces
+        })
+        .min()
+        .unwrap_or(0);
+
+    // Remove that many spaces from the beginning of each line
+    lines.iter()
+        .map(|line| {
+            if line.trim().is_empty() {
+                return String::new();
+            }
+
+            let mut count = 0;
+            let mut chars = line.chars().peekable();
+            
+            // Skip initial spaces up to min_indent
+            while count < min_indent && chars.peek().is_some() {
+                match chars.peek() {
+                    Some(' ') => {
+                        chars.next();
+                        count += 1;
+                    },
+                    Some('\t') => {
+                        chars.next();
+                        count += 4;
+                    },
+                    _ => break,
+                }
+            }
+            
+            // Return the remaining characters
+            chars.collect::<String>()
+        })
+        .collect::<Vec<String>>()
+        .join("\n")
+}