Revise using string interpolation.

CHANGELOG.md

@@ -1,7 +1,7 @@
 Rhai Release Notes
 ==================
 
-This version adds string interpolation.
+This version adds string interpolation with `` `... ${`` ... ``} ...` `` syntax.
 
 Version 0.19.16
 ===============

benches/parsing.rs

@@ -93,8 +93,8 @@ fn bench_parse_primes(bench: &mut Bencher) {
                 }
             }
             
-            print("Total " + total_primes_found + " primes.");
+            print(`Total ${total_primes_found} primes.`);
-            print("Run time = " + now.elapsed + " seconds.");
+            print(`Run time = ${now.elapsed} seconds.`);
         "#;
 
     let mut engine = Engine::new();

examples/threading.rs

@@ -40,9 +40,9 @@ fn main() {
 
                     loop {
                         let x = get();
-                        print("Script Read: " + x);
+                        print(`Script Read: ${x}`);
                         x += 1;
-                        print("Script Write: " + x);
+                        print(`Script Write: ${x}`);
                         put(x);
                     }
                 "#,

scripts/fibonacci.rhai

@@ -21,9 +21,9 @@ for n in range(0, 5) {
 	result = fib(target);
 }
 
-print("Finished. Run time = " + now.elapsed + " seconds.");
+print(`Finished. Run time = ${now.elapsed} seconds.`);
 
-print("Fibonacci number #" + target + " = " + result);
+print(`Fibonacci number #${target} = ${result}`);
 
 if result != 317_811 {
     print("The answer is WRONG! Should be 317,811!");

scripts/for1.rhai

@@ -4,7 +4,7 @@ let arr = [1, 2, 3, 4];
 
 for a in arr {
     for b in [10, 20] {
-        print(a + "," + b);
+        print(`${a}, ${b}`);
     }
 
     if a == 3 { break; }

scripts/for2.rhai

@@ -1,6 +1,6 @@
 const MAX = 1_000_000;
 
-print("Iterating an array with " + MAX + " items...");
+print(`Iterating an array with ${MAX} items...`);
 
 print("Ready... Go!");
 
@@ -18,5 +18,5 @@ for i in list {
     sum += i;
 }
 
-print("Sum = " + sum);
+print(`Sum = ${sum}`);
-print("Finished. Run time = " + now.elapsed + " seconds.");
+print(`Finished. Run time = ${now.elapsed} seconds.`);

scripts/mat_mul.rhai

@@ -68,4 +68,4 @@ for i in range(0, SIZE) {
 }
 */
 
-print("Finished. Run time = " + now.elapsed + " seconds.");
+print(`Finished. Run time = ${now.elapsed} seconds.`);

scripts/oop.rhai

@@ -7,7 +7,7 @@ let last_value = ();
 let obj1 = #{
     _data: 42,                                  // data field
     get_data: || this._data,                    // property getter
-    action: || print("Data=" + this._data),     // method
+    action: || print(`Data=${this._data}`),     // method
     update: |x| {                               // property setter
         this._data = x;
         last_value = this._data;                // capture 'last_value'
@@ -38,4 +38,4 @@ if obj2.get_data() > 0 {                        // property access
     obj2.update(42);                            // call method
 }
 
-print("Should be 84: " + last_value);
+print(`Should be 84: ${last_value}`);

scripts/primes.rhai

@@ -25,8 +25,8 @@ for p in range(2, MAX_NUMBER_TO_CHECK) {
     }
 }
 
-print("Total " + total_primes_found + " primes <= " + MAX_NUMBER_TO_CHECK);
+print(`Total ${total_primes_found} primes <= ${MAX_NUMBER_TO_CHECK}`);
-print("Run time = " + now.elapsed + " seconds.");
+print(`Run time = ${now.elapsed} seconds.`);
 
 if total_primes_found != 78_498 {
     print("The answer is WRONG! Should be 78,498!");

scripts/speed_test.rhai

@@ -10,4 +10,4 @@ while x > 0 {
     x -= 1;
 }
 
-print("Finished. Run time = " + now.elapsed + " seconds.");
+print(`Finished. Run time = ${now.elapsed} seconds.`);

scripts/string.rhai

@@ -11,17 +11,18 @@ print("foo" >= "bar");          // string comparison
 print("the answer is " + 42);   // string building using non-string types
 
 let s = "\u2764 hello, world! \U0001F603"; // string variable
-print("length=" + s.len);       // should be 17
+print(`length=${s.len}`);       // should be 17
 
 s[s.len-3] = '?';               // change the string
-print("Question: " + s);        // should print 'Question: hello, world?'
+print(`Question: ${s}`);        // should print 'Question: hello, world?'
 
 // Line continuation:
 let s = "This is a long \
          string constructed using \
          line continuation";
 
-print("One string: " + s);
+// String interpolation
+print(`One string: ${s}`);
 
 // Multi-line literal string:
 let s = `

scripts/strings_map.rhai

@@ -75,7 +75,7 @@ let keys = [];
 for animal in animals {
   for adjective in adjectives {
     for adverb in adverbs {
-      keys.push(adverb + " " + adjective + " " + animal)
+      keys.push(`${adverb} ${adjective} ${animal}`)
     }
   }
 }
@@ -99,5 +99,5 @@ for key in keys {
   map.remove(key);
 }
 
-print("Sum = " + sum);
+print(`Sum = ${sum}`);
-print("Finished. Run time = " + now.elapsed + " seconds.");
+print(`Finished. Run time = ${now.elapsed} seconds.`);

src/ast.rs

@@ -384,7 +384,7 @@ impl AST {
     ///             "#)?;
     ///
     /// let ast2 = engine.compile(r#"
-    ///                 fn foo(n) { "hello" + n }
+    ///                 fn foo(n) { `hello${n}` }
     ///                 foo("!")
     ///             "#)?;
     ///
@@ -395,7 +395,7 @@ impl AST {
     ///
     /// // 'ast' is essentially:
     /// //
-    /// //    fn foo(n) { "hello" + n } // <- definition of first 'foo' is overwritten
+    /// //    fn foo(n) { `hello${n}` } // <- definition of first 'foo' is overwritten
     /// //    foo(1)                    // <- notice this will be "hello1" instead of 43,
     /// //                              //    but it is no longer the return value
     /// //    foo("!")                  // returns "hello!"
@@ -436,7 +436,7 @@ impl AST {
     ///                 "#)?;
     ///
     /// let ast2 = engine.compile(r#"
-    ///                 fn foo(n) { "hello" + n }
+    ///                 fn foo(n) { `hello${n}` }
     ///                 foo("!")
     ///             "#)?;
     ///
@@ -447,7 +447,7 @@ impl AST {
     ///
     /// // 'ast1' is essentially:
     /// //
-    /// //    fn foo(n) { "hello" + n } // <- definition of first 'foo' is overwritten
+    /// //    fn foo(n) { `hello${n}` } // <- definition of first 'foo' is overwritten
     /// //    foo(1)                    // <- notice this will be "hello1" instead of 43,
     /// //                              //    but it is no longer the return value
     /// //    foo("!")                  // returns "hello!"
@@ -490,7 +490,7 @@ impl AST {
     ///             "#)?;
     ///
     /// let ast2 = engine.compile(r#"
-    ///                 fn foo(n) { "hello" + n }
+    ///                 fn foo(n) { `hello${n}` }
     ///                 fn error() { 0 }
     ///                 foo("!")
     ///             "#)?;
@@ -574,7 +574,7 @@ impl AST {
     ///                 "#)?;
     ///
     /// let ast2 = engine.compile(r#"
-    ///                 fn foo(n) { "hello" + n }
+    ///                 fn foo(n) { `hello${n}` }
     ///                 fn error() { 0 }
     ///                 foo("!")
     ///             "#)?;

src/fn_args.rs

@@ -41,7 +41,7 @@ pub trait FuncArgs {
     ///
     /// let ast = engine.compile(r#"
     ///         fn hello(x, y, z) {
-    ///             if x { "hello " + y } else { y + z }
+    ///             if x { `hello ${y}` } else { y + z }
     ///         }
     /// "#)?;
     ///

tests/call_fn.rs

@@ -81,7 +81,7 @@ fn test_call_fn_args() -> Result<(), Box<EvalAltResult>> {
     let ast = engine.compile(
         r#"
             fn hello(x, y, z) {
-                if x { "hello " + y } else { y + z }
+                if x { `hello ${y}` } else { y + z }
             }
         "#,
     )?;

tests/modules.rs

@@ -315,7 +315,7 @@ fn test_module_from_ast() -> Result<(), Box<EvalAltResult>> {
         
             // Final variable values become constant module variable values
             foo = calc(foo);
-            hello = "hello, " + foo + " worlds!";
+            hello = `hello, ${foo} worlds!`;
 
             export
                 x as abc,