feat: add while loop token, parser support, CODE_LOOP opcode, and patchJump helper

Add TOKEN_WHILE to the token enum and keyword lookup in the compiler, enabling the parser to recognize 'while' statements. Introduce the CODE_LOOP opcode in the VM for backward jumps, and implement the patchJump helper to resolve forward jump offsets during compilation. Include comprehensive test cases for while loops covering single-expression bodies, block bodies, newline handling, and null result semantics.
2013-11-18 06:38:59 +00:00
parent 9c663aa13c
commit dc2f053d76
5 changed files with 277 additions and 158 deletions
@@ -0,0 +1,38 @@
+// Evaluate the 'then' expression if the condition is true.
+if (true) io.write("good") // expect: good
+if (false) io.write("bad")
+
+// Evaluate the 'else' expression if the condition is false.
+if (true) io.write("good") else io.write("bad") // expect: good
+if (false) io.write("bad") else io.write("good") // expect: good
+
+// Allow statements for then branch.
+if (true) { io.write("block") } // expect: block
+if (true) if (true) io.write("double") // expect: double
+
+// Allow statements for else branch.
+if (false) null else { io.write("block") } // expect: block
+if (false) null else if (true) io.write("double") // expect: double
+
+// Return the 'then' expression if the condition is true.
+var a = if (true) "good"
+io.write(a) // expect: good
+
+// Return null if the condition is false and there is no else.
+var b = if (false) "bad"
+io.write(b) // expect: null
+
+// Return the 'else' expression if the condition is false.
+var c = if (false) "bad" else "good"
+io.write(c) // expect: good
+
+// Assignment in if condition.
+if (a = true) io.write(a) // expect: true
+
+// Newline after "if".
+if
+(true) io.write("good") // expect: good
+
+// Newline after "else".
+if (false) io.write("bad") else
+io.write("good") // expect: good