Merge pull request #25 from Lilit0x/functions/replace

REPLACE String Function: #13
AmrDeveloper · Sep 12, 2023 · 16f8824 · 16f8824
2 parents fe42610 + cf944a7
commit 16f8824
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diff --git a/crates/gitql-ast/src/function.rs b/crates/gitql-ast/src/function.rs
@@ -29,6 +29,7 @@ lazy_static! {
         map.insert("left", text_left);
         map.insert("datalength", text_datalength);
         map.insert("char", text_char);
+        map.insert("replace", text_replace);
         map.insert("substring", text_substring);
 
         // Date functions
@@ -135,6 +136,12 @@ lazy_static! {
             },
         );
         map.insert(
+            "replace",
+            Prototype {
+                parameters: vec![DataType::Text, DataType::Text, DataType::Text],
+          },
+        );
+        map.insert({
             "substring",
             Prototype {
                 parameters: vec![DataType::Text, DataType::Number, DataType::Number],
@@ -250,6 +257,26 @@ fn text_char(inputs: Vec<Value>) -> Value {
     return Value::Text("".to_string());
 }
 
+fn text_replace(inputs: Vec<Value>) -> Value {
+    let text = inputs[0].as_text();
+    let old_string = inputs[1].as_text();
+    let new_string = inputs[2].as_text();
+
+    let mut result = String::new();
+    let mut end = 0;
+    for (begin, matched_part) in text
+        .to_lowercase()
+        .match_indices(&old_string.to_lowercase())
+    {
+        result.push_str(&text.get(end..begin).unwrap());
+        result.push_str(&new_string);
+        end = begin + matched_part.len();
+    }
+    result.push_str(&text.get(end..text.len()).unwrap());
+
+    return Value::Text(result);
+  }
+
 fn text_substring(inputs: Vec<Value>) -> Value {
     let text = inputs[0].as_text();
     //according to the specs, a stirng starts at position 1.

diff --git a/docs/function/functions.md b/docs/function/functions.md
@@ -18,6 +18,7 @@ note that all functions names are case-insensitive.
 | LEFT       | Text, Number | Text   | Extracts a number of characters from a string (starting from left). |
 | DATALENGTH | Text         | Number | Returns the number of bytes used to represent an expression.        |
 | CHAR       | Number       | Text   | Returns the character based on the ASCII code.                      |
+| REPLACE    | Text, Text, Text | Text  | Replaces all occurrences of a substring within a string, with a new substring. |
 | SUBSTRING  | Text, Number, Number | Text | Extracts some characters from a string.                       |
 
 ### String functions samples
@@ -33,6 +34,7 @@ SELECT name, ASCII(name) AS firstCharAscii FROM commits
 SELECT LEFT("AmrDeveloper", 3) AS extract
 SELECT DATALENGTH("AmrDeveloper") as bytelength
 SELECT CHAR(345) AS code
+SELECT REPLACE("ABC ABC ABC", "a", "c") as replacedText
 SELECT name, SUBSTRING(name, 1, 5) AS extract FROM commits
 ```