YAPC::EU 2018 Glasgow Update!

Task/Strip-comments-from-a-string/Factor/strip-comments-from-a-string.factor

@@ -0,0 +1,3 @@
+USE: sequences.extras
+: strip-comments ( str -- str' )
+    [ "#;" member? not ] take-while "" like ;

Task/Strip-comments-from-a-string/Forth/strip-comments-from-a-string-1.fth

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+\ Rosetta Code Strip Comment
+
+: LASTCHAR ( addr len -- addr len c) 2DUP + 1- C@ ;
+
+: COMMENT? ( char -- ? )  S" #;"  ROT SCAN NIP ; \ is char '#' or ';'
+
+: -COMMENT   ( addr len -- addr len') \ removes # or ; comments
+            BEGIN
+              LASTCHAR COMMENT? 0=
+             WHILE                    \ while not a comment char...
+                1-                    \ reduce length by 1
+            REPEAT
+            1-  ;                     \ remove 1 more (the comment char)
+
+\ -TRAILING is resident in desktop Forth systems like Swift Forth
+\ shown here for demonstration
+: -TRAILING  ( adr len -- adr len')    \ remove trailing spaces
+             BEGIN
+               LASTCHAR BL =
+             WHILE                     \ while lastchar = blank char
+               1-                      \ reduce length by 1
+             REPEAT  ;
+
+: COMMENT-STRIP ( addr len -- addr 'len)  -COMMENT  -TRAILING ;

Task/Strip-comments-from-a-string/Forth/strip-comments-from-a-string-2.fth

@@ -0,0 +1,2 @@
+S" apples, pears # and bananas"  COMMENT-STRIP TYPE apples, pears ok
+S" apples, pears ; and bananas"  COMMENT-STRIP TYPE apples, pears ok

Task/Strip-comments-from-a-string/JavaScript/strip-comments-from-a-string-3.js

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+(() => {
+    'use strict';
+
+    const main = () => {
+
+        const src = `apples, pears # and bananas
+apples, pears ; and bananas`;
+
+        return unlines(
+            map(preComment(chars(';#')),
+                lines(src)
+            )
+        );
+    };
+
+    // preComment :: [Char] -> String -> String
+    const preComment = cs => s =>
+        strip(
+            takeWhile(
+                curry(flip(notElem))(cs),
+                s
+            )
+        );
+
+    // GENERIC FUNCTIONS ------------------------------
+
+    // chars :: String -> [Char]
+    const chars = s => s.split('');
+
+    // curry :: ((a, b) -> c) -> a -> b -> c
+    const curry = f => a => b => f(a, b);
+
+    // flip :: (a -> b -> c) -> b -> a -> c
+    const flip = f => (a, b) => f.apply(null, [b, a]);
+
+    // lines :: String -> [String]
+    const lines = s => s.split(/[\r\n]/);
+
+    // map :: (a -> b) -> [a] -> [b]
+    const map = (f, xs) => xs.map(f);
+
+    // notElem :: Eq a => a -> [a] -> Bool
+    const notElem = (x, xs) => -1 === xs.indexOf(x);
+
+    // strip :: String -> String
+    const strip = s => s.trim();
+
+    // takeWhile :: (a -> Bool) -> [a] -> [a]
+    // takeWhile :: (Char -> Bool) -> String -> String
+    const takeWhile = (p, xs) => {
+        let i = 0;
+        const lng = xs.length;
+        while ((i < lng) && p(xs[i]))(i = i + 1);
+        return xs.slice(0, i);
+    };
+
+    // unlines :: [String] -> String
+    const unlines = xs => xs.join('\n');
+
+    // MAIN ---
+    return main();
+})();