Added the sequence parser combinator to parseq. This closes #42

libraries/qsl/parseq.q

@@ -437,6 +437,20 @@ sepBy1:{[pa;sep;ps]
     ];
   :(`s`cp`errp`errs`ast)!(s;k;0N;();res)
   };
+
+/F/ parses a list of parsers sequentially. Fails if any of the parsers fails.
+/P/ lpars:LIST[FUNCTION} - a list of parsers
+/R/ :LIST[ANY] - list of results returned by lpars
+sequence:{[lpars;ps]
+    if[0N<>ps`errp;:ps];
+    if[0~count lpars;ps[`ast]:();:ps];
+    ps1:(first lpars) ps;
+    if[0N<>ps1`errp;:ps1];
+    ps2:sequence[1_lpars] ps1;
+    if[0N<>ps2`errp;:ps2];
+    ps2[`ast]:(enlist ps1`ast),ps2`ast;
+    :ps2
+    };
 
 /F/ Parses zero or more occurrences of a pattern, seperated and ended by a separator. Always succeeds.
 /P/ pa - the parser to be applied repeatedly

libraries/qsl/test/parseq_test.q

@@ -85,9 +85,12 @@ system "l lib/qspec/qspec.q";
     parseTest[{notFollowedBy[eof] pstring["abc"] x}; "abc"] mustmatch ("error at position 3";"notFollowedBy:excluded end pattern encountered");
     // oneChar and empty string
     (parseTest[butNot[anyChar;char")"]] "") mustmatch ("error at position 0";"unexpected end of input");
-  (parseTest[.par.anyChar] "") mustmatch ("error at position 0";"unexpected end of input");
-  (parseTest[{.par.between[.par.pstring["${"];.par.char["}"];digit] x }] "test") mustmatch ("error at position 0";"expected ${");
+    (parseTest[.par.anyChar] "") mustmatch ("error at position 0";"unexpected end of input");
+    (parseTest[{.par.between[.par.pstring["${"];.par.char["}"];digit] x }] "test") mustmatch ("error at position 0";"expected ${");
     (parseTest[{.par.between[.par.pstring["${"];.par.char["}"];digit] x }] "${3}") mustmatch "3";
+    (parseTest[sequence(digit;pstring" is a digit")] "3 is a digit") mustmatch ("3";" is a digit");
+    (parseTest[sequence(char"(";pstring"abc";char")")] "(abc)") mustmatch ("(";"abc";")");
+
     };
   };