update

Task/Reverse-a-string/Aime/reverse-a-string.aime

@@ -0,0 +1,23 @@
+text
+reverse(text s)
+{
+    data b;
+    integer i;
+
+    i = length(s);
+    while (i) {
+        i -= 1;
+        b_insert(b, -1, character(s, i));
+    }
+
+    return b_string(b);
+}
+
+integer
+main(void)
+{
+    o_text(reverse("Hello, World!"));
+    o_byte('\n');
+
+    return 0;
+}

Task/Reverse-a-string/FBSL/reverse-a-string-1.fbsl

@@ -1,8 +1,8 @@
 Function StrRev1(ByVal $p1)
 	dim $b = ""
-	repeat len(p1)
-		b = b & right(p1,1)
-		p1 = left(p1,len(p1)-1)
-	end repeat
+	REPEAT len(p1)
+		b = b & RIGHT(p1,1)
+		p1 = LEFT(p1,LEN(p1)-1)
+	END REPEAT
 	return b
 End Function

Task/Reverse-a-string/FBSL/reverse-a-string-2.fbsl

@@ -1,8 +1,7 @@
 Function StrRev2(ByVal $p1)
-	dim $b = ""
-	dim %i
-	for i = len(p1) downto 1
-		b = b & mid(p1,i,1)
+	dim $b = "", %i
+	for i = len(p1) DOWNTO 1
+		b = b & MID(p1,i,1)
 	next
 	return b
 End Function

Task/Reverse-a-string/FBSL/reverse-a-string-5.fbsl

@@ -0,0 +1,49 @@
+DYNASM RevStr(BYVAL s AS STRING) AS STRING
+   // get length of string
+   // divide by two
+   // setup pointers to head and tail
+   // iterate from 1 to (length \ 2)
+   //   swap head with tail
+   //   increment head pointer
+   //   decrement tail pointer
+
+   ENTER 0, 0 // = PUSH EBP: MOV EBP, ESP
+   PUSH EBX // by Windows convention EBX, EDI, ESI must be saved before modification
+
+   MOV EAX, s // get string pointer
+   MOV ECX, EAX // duplicate it
+
+   .WHILE BYTE PTR [ECX] <> 0
+
+	INC ECX // propagate to tail
+
+   .WEND
+
+   MOV EDX, ECX // duplicate tail pointer
+   DEC EDX // set it to last byte before trailing zero
+
+   SUB ECX, EAX // get length in ECX in 1 CPU cycle
+   SHR ECX, 1 // get length \ 2 in 1 CPU cycle; that's the beauty of power-of-two division
+
+   .WHILE ECX > 0
+
+      MOV BL, [EDX] // no need to XOR; just overwrite BL and BH contents
+      MOV BH, [EAX] // DynAsm deduces data size from destination register sizes
+
+      MOV [EDX], BH // ditto, source register sizes
+      MOV [EAX], BL
+
+      INC EAX // propagate pointers
+      DEC EDX
+
+      DEC ECX // decrement counter
+
+   .WEND
+
+   // point to start of string again
+   MOV EAX, s // MOV = 1 CPU cycle, PUSH + POP = 2 CPU cycles
+
+   POP EBX // by Windows convention ESI, EDI, EBX must be restored if modified
+   LEAVE // = POP EBP
+   RET
+END DYNASM

Task/Reverse-a-string/Raven/reverse-a-string.raven

@@ -0,0 +1 @@
+"asdf" reverse

Task/Reverse-a-string/UNIX-Shell/reverse-a-string.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+str=abcde
+
+for((i=${#str}-1;i>=0;i--)); do rev="$rev${str:$i:1}"; done
+
+echo $rev