haskell alex: parse error on import? -


i've took haskell , alex/happy because wanted write parser. however, ran problem:

source: lexer.x

{ module valkenlexer  strip :: string -> string strip s = take ((length s) - 2) (drop 1 s) }  %wrapper "basic"  $digit = 0-9 $alpha = [a-za-z]  tokens :-   $white+                           ;   $alpha+                               { \s -> tokident s }   \"[^\"]*\"                       { \s -> tokstr strip(s) }   =                                     { \s -> tokslash}   \|                                    { \s -> tokpipe }   \/                                    { \s -> tokslash }   \n                                    { \s -> tokeol}   \%$alpha+                              { \s -> tokvar (drop 1 s)}  {  data token = tokident string            | tokstr string            | tokeq            | tokpipe            | tokslash            | tokeol            | tokvar string              deriving (eq,show)  }

and got:

\->>> alex lexer.x && ghc lexer.hs [1 of 1] compiling valkenlexer      ( lexer.hs, lexer.o )  lexer.hs:15:1: parse error on input `import'

what doing wrong?

as daniel wagner predicted, function definitions need go on footer. can put module declaration , import statements on header. additionally, need change tokstr strip(s) tokstr (strip s)

{ module valkenlexer }  %wrapper "basic"  $digit = 0-9 $alpha = [a-za-z]  tokens :-   $white+                           ;   $alpha+                               { \s -> tokident s }   \"[^\"]*\"                       { \s -> tokstr (strip s) }   =                                     { \s -> tokslash}   \|                                    { \s -> tokpipe }   \/                                    { \s -> tokslash }   \n                                    { \s -> tokeol}   \%$alpha+                              { \s -> tokvar (drop 1 s)}  { strip :: string -> string strip s = take ((length s) - 2) (drop 1 s)  data token = tokident string            | tokstr string            | tokeq            | tokpipe            | tokslash            | tokeol            | tokvar string              deriving (eq,show) }

Comments

Post a Comment

Popular posts from this blog

java.util.scanner - How to read and add only numbers to array from a text file -

i'm learning java , have question regarding reading file want read numbers file contains strings well. here example of file: 66.56 "3 java 3-43 5-42 2.1 1 and here coding: public class test { public static void main (string [] args){ if (0 < args.length) { file x = new file(args[0]); try{ scanner in = new scanner( new fileinputstream(x)); arraylist<double> test = new arraylist<>(); while(in.hasnext()){ if(in.hasnextdouble()){ double f=in.nextdouble(); test.add(f);} else {in.next();} } catch(ioexception e) { system.err.println("exception during reading: " + e); } } my problem add 66.56,2.1 , 1 doesn't add 3 after "3 or ignores 3-43 , 5-42 can tell me how skip strings , add doubles here? thanks all said 3 ie; "3, 3-43 , 4-42 strings either u read string , split , check number @ " , - or put in space between characters , integers. jvm after compilation tre...
Read more

rewrite - Trouble with Wordpress multiple custom querystrings -

i'm working on adding multiple querystring , doesn't seem work. i've found codes seems work others might i'm missing something. i want like: http://mydomain.com/board/?getyear=2013&getsometext2=sometext to http://mydomain.com/board/2013/sometext/ i added code below functions.php file. doesn't seem work should though. this works. echoing querystring gets both variable without problem. http://mydomain.com/board/2013/sometext/ but doesn't. tested querystring vis isset() seems nothing being set/get http://mydomain.com/board/2013/ function add_query_vars($vars) { $vars[] = "getyear"; $vars[] = "getsometext2"; return $vars; } add_filter('query_vars', 'add_query_vars'); function add_rewrite_rules($arules) { $anewrules = array('board/([^/]+)/([^/]+)/?$' => 'index.php?pagename=board&getyear=$matches[1]&getsometext2=$matches[2]'); $arules = $a...
Read more