lib: change `ord()` to always return single byte value

The most common usecase is extracting the value of a single byte at a
specific offset, e.g. to scan a string char-by-char to construct a hash.

Furthermore, constructing an array which contains the results of multiple
`ord()` invocations is trivial while efficiently extracting a single byte
value without the overhead of an intermediate array is not.

Due to that, change `ord()` to always return a single integer byte value
at the offset specified as second argument or at offset 0 in case no
argument was supplied.

That means that `ord("Abc", 0, 1, 2)` will now return `65` instead of the
former `[ 65, 98, 99 ]` result.

Code relying on the former behaviour should either perform multiple calls
to `ord()`, passing different offsets each time or switch to the `struct`
module which allows efficient unpacking of string data.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 17 insertions, 18 deletions

diff --git a/tests/custom/03_stdlib/13_ord b/tests/custom/03_stdlib/13_ord
index 3a69228..7edeff0 100644
--- a/tests/custom/03_stdlib/13_ord
+++ b/tests/custom/03_stdlib/13_ord
@@ -1,19 +1,14 @@
-The `ord()` function extracts the byte values of characters within the
-given input string at different offsets, depending on the arguments.
+The `ord()` function extracts the byte value of the character within the
+given input string at the given offset.
 
-Without further arguments, the function will return the byte value of
-the first character within the given string.
-
-If one or more offset arguments are given, the function returns an array
-containing the byte values of each character at the corresponding offset.
+If the offset argument is omitted, the byte value of the first character
+is returned.
 
 Returns `null` if the given input string argument is not a string.
 
-Returns `null` if the given input string is empty and no offset arguments
-are provided.
+Returns `null` if the given input string is empty.
 
-If invalid offsets are given, the corresponding values within the result
-array will be set to `null`.
+Returns `null` if the given offset value is invalid.
 
 Invalid offsets are non-integer values or integers equal to or larger than
 the length of the input string. Negative offsets are converted to positive
@@ -26,11 +21,13 @@ too large, the offset is considered invalid.
 	print(join("\n", [
 		ord(123),
 		ord(""),
+		ord("abcd", "inval"),
 		ord("abcd"),
 		ord("abcd", 0),
-		ord("abcd", 1, 3, 2),
-		ord("abcd", -1, -2),
-		ord("abcd", -10, 10)
+		ord("abcd", 1),
+		ord("abcd", -1),
+		ord("abcd", 10),
+		ord("abcd", -10)
 	]), "\n");
 %}
 -- End --
@@ -38,9 +35,11 @@ too large, the offset is considered invalid.
 -- Expect stdout --
 null
 null
+null
+97
 97
-[ 97 ]
-[ 98, 100, 99 ]
-[ 100, 99 ]
-[ null, null ]
+98
+100
+null
+null
 -- End --