Data commit

Task/Align-columns/Picat/align-columns.picat

@@ -0,0 +1,46 @@
+import util.
+
+main =>
+    Text =
+"Given$a$text$file$of$many$lines,$where$fields$within$a$line$
+are$delineated$by$a$single$'dollar'$character,$write$a$program
+that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$
+column$are$separated$by$at$least$one$space.
+Further,$allow$for$each$word$in$a$column$to$be$either$left$
+justified,$right$justified,$or$center$justified$within$its$column.",
+    Lines = split(Text,"\n"),
+    Lines = [Line1|_],
+    N = len(split(strip(Line1,"$ "), "$")),   % number of columns
+    WidthArr = {0 : _ in 1..N},
+    foreach (Line in Lines)
+        Words = split(strip(Line,"$ "), "$"),
+        foreach ({I,Word} in zip(1..N, Words))
+            WidthArr[I] := max(WidthArr[I], len(Word))
+        end
+    end,
+    foreach (I in 1..N)
+        WidthArr[I] := WidthArr[I]+1          % separate cols by at least one space
+    end,
+    foreach (Align in [left, right, center])
+        output_lines(Lines,N,WidthArr,Align),
+        nl,nl
+    end.
+
+output_lines(Lines,N,WidthArr,Align) =>
+    foreach (Line in Lines)
+        Words = split(strip(Line,"$ "), "$"),
+        foreach ({I,Word} in zip(1..N, Words))
+            output_word(Word,WidthArr[I],Align)
+        end,
+        nl
+    end.
+
+output_word(Word,Width,left) =>
+    printf("%-*s",Width,Word).
+output_word(Word,Width,right) =>
+    printf("%*s",Width,Word).
+output_word(Word,Width,_) =>
+    Pad = len(Word)-Width,
+    Pad1 is Pad div 2,
+    Pad2 is Pad-Pad1,
+    printf("%*s%s%*s",Pad1,"",Word,Pad2,"").