Palindrome detection: Difference between revisions
→{{header|ed}}: More reliable and even-length-friendly palindrome detection.
(→{{header|Uiua}}: Added an extra credit solution) |
(→{{header|ed}}: More reliable and even-length-friendly palindrome detection.) |
||
| (2 intermediate revisions by the same user not shown) | |||
Line 1,911:
;;(equal? (string->list string) (reverse (string->list string)))))
</syntaxhighlight>
=={{header|ed}}==
A limitation: due to ed having no built-in loops, the part with palindrome beginning/end matching has to be repeated as many times as there are palindrome levels. As a sane default, 15 is used here.
<syntaxhighlight lang="sed">
# by Artyom Bologov
H
,p
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
g/^(.)(.*)\1$/s//\2/
v/^(.)(.+)\1$|^.?$/s/.*/Not a palindrome!/
g/^.?$/s//Palindrome!/
,p
Q
</syntaxhighlight>
{{out}}
<pre>$ cat palindrome.ed | ed -lEGs palindrome.input
Newline appended
rotor
racecar
level
rosetta
oppo
Palindrome!
Palindrome!
Palindrome!
Not a palindrome!
Palindrome!</pre>
=={{header|Eiffel}}==
| |||