seqlings 3.0.7

Interactive exercises for learning Seq, a stack-based programming language
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# Exercise: Handling Decode Errors
#
# Decode operations can fail on invalid input.
# Always check the Bool return value!
#
# Common errors:
# - Invalid characters in encoded string
# - Wrong padding in Base64
# - Odd-length hex strings
#
# Your task: Implement safe decoding with error messages
# When done, delete the marker line below.

# I AM NOT DONE

: safe-base64-decode ( String -- String )
    # Decode base64, return "ERROR" on failure
    # Your code here
    drop "ERROR"
;

: safe-hex-decode ( String -- String )
    # Decode hex, return "ERROR" on failure
    # Your code here
    drop "ERROR"
;

: test-errors ( -- )
    # Valid base64
    "SGVsbG8=" safe-base64-decode
    # Do not edit below this line
    "Hello" test.assert-eq

    # Invalid base64 (bad characters)
    "Not!!!Valid" safe-base64-decode
    "ERROR" test.assert-eq

    # Valid hex
    "48656c6c6f" safe-hex-decode
    "Hello" test.assert-eq

    # Invalid hex (non-hex characters)
    "xyz123" safe-hex-decode
    "ERROR" test.assert-eq

    # Invalid hex (odd length)
    "123" safe-hex-decode
    "ERROR" test.assert-eq
;