Hi what would be appropriate to recognize string in a lex.
I have already tried
enter code here
import java_cup.runtime.*;
%%
%cup
%line
NUM = [0-9]
ID = [a-zA-Z]
Pun= [:=;##$^~]
WhiteSpace = [ \t\r\n\f]
SDQuo = [\"]
%%
({SDQuo}+) ({ID}|{NUM})* ({SDQuo}+) { return new Symbol(sym.STR, new String(yytext()));}
but the macro fail to be recognized.
The error message that I kept getting is:
Processing first section -- user code.
Processing second section -- JLex declarations.
Processing third section -- lexical rules.
Creating NFA machine representation.
Error: Parse error at line 39.
Description: Missing brace at start of lexical action.
Parse error.
Loose the = signs in the definitions of NUM etc. and don't place them between %%. Instead place the last rule between %%.
Related
I am new to antler and creating a parse tree. I am trying to create tokens that include a special character, but when I do so it gives me an input mismatch.
I have tried to add a special character to my LEXER rules by adding a '.' at the end, however when I do so it give me the error of input mismatch. The snippet of code that I am trying will work on its own but not as part of the entire code.
This is the code I have so far...
grammar Grammar4;
r : WORD', 'NUMBER', 'BOOL', 'SENT+;
BOOL : 'true' | 'false';
WORD : [a-zA-Z]+;
NUMBER : [0-9]+;
SENT : [a-zA-Z ]+;
WS : [ \t\r\n]+ -> skip ;
If I add a period at the end of SENT to allow for special characters ([a-zA-Z ]+.;) then I get an input mismatch. If I take that line out and use it independently of the rest than I can have a sentence like, "How are you today!" and have it tokenize fine.Any help is greatly appreciated.
Edited for clarity:
I am trying to parse a statement like, Alex, 31, false, I let the dog out! (note that I can get everything to parse as an individual token except the last special character and I would like "I let the dog out!" to be one token.
I have a file foo that I'd like to copy into a table.
\copy stage.from_csv FROM '/path/foo.dat' CSV;
If foo has an error like column mismatch or bad type, the return error is normal:
CONTEXT: COPY from_csv, line 5, column report_year: "aa"
However, if the error is caused by an extraneous quotation mark, the reported line number is always one greater than the size of the file.
CONTEXT: COPY from_csv, line 11: "02,2004,"05","123","09228","00","SUSX","PR",30,,..."
The source file has 10 lines, and I placed the error in line 5. If you examine the information in the CONTEXT message, it contains the line 5 data, so I know postgres can identify the row itself. However, it cannot identify the row by number. I have done this with a few different file lengths and the returned line number behavior is consistent.
Anyone know the cause and/or how to get around this?
That is because the error manifests only at the end of the file.
Look at this CSV file:
"google","growing",1,2
"google","growing",2,3
"google","falling","3,4
"google","growing",4,5
"yahoo","growing",1,2
There is a bug in the third line, an extra " has been added before the 3.
Now to parse a CSV file, you first read until you hit the next line break.
But be careful, line breaks that are within double quotes don't count!
So all of the line breaks are part of a quoted string, and the line continues until the end of file.
Now that we have read our line, we can continue parsing it and notice that the number of quotes is unbalanced. Hence the error message:
ERROR: unterminated CSV quoted field
CONTEXT: COPY stock, line 6: ""google","falling","3,4
"google","growing",4,5
"yahoo","growing",1,2
"
In a nutshell: the error does not occur until we have reached the end of file.
According to wikipedia :
A quine is a non-empty computer program which takes no input and produces a copy of its own source code as its only output
I saw this piece of perl code and am not able to figure out how it works.
Save the following line in file /tmp/p and run the file as perl /tmp/p:
Illegal division by zero at /tmp/p line 1.
The output of perl /tmp/p is:
Illegal division by zero at /tmp/p line 1.
How is the code working?
First, try to run it with warnings turned on:
$ perl -w p
Unquoted string "at" may clash with future reserved word at p line 1.
Unquoted string "tmp" may clash with future reserved word at p line 1.
Argument "tmp" isn't numeric in division (/) at p line 1.
Argument "at" isn't numeric in division (/) at p line 1.
The first two warnings are from the compile phase.
Let's look at the Deparse output:
$ perl -MO=Deparse p
'division'->Illegal('zero'->by('at' / 'tmp' / 'line'->p(1)));
p syntax OK
In essence, the value of at divided by tmp divided by the return value of another method invocationp is passed as an argument to the method by invoked on the class 'zero'. at and tmp are considered to be strings, and their numeric values are zero. Therefore, at/tmp results in the illegal division by zero error.
You will get the same error if you change the file's contents to
Stackoverflow hacker news one at /tmp/p line 1.
If you are wondering how Illegal division becomes 'division'->Illegal, see indirect object syntax, and avoid using it.
I would prefer to see you concentrating on improving the quality of your Perl code, rather than investigating obscure corners
But the answer is that the line is parsed as
'division'->Illegal('zero'->by('at' / 'tmp' / 'line'->p(1)));
and Perl uses zero for 'at' and 'tmp' because they are not valid numeric strings, so the first action is to evaluate 0 / 0 which throws the error
I have an application that translates the .csv files I currently have into the correct format I need. But, the files I that I do have seem to have '"' double quotes around them, as seen in this image, which will not work with the program. As a result, I'm using this command to remove them:
for m = 1:currentsize(1)
for n = 1:currentsize(2)
replacement{m,n} = strrep(current{m,n}, '"', '');
end
end
I'm not entirely sure that this works though, as it spits this back at me as it runs:
Warning: Inputs must be character arrays or cell arrays of strings.
When I open the file in matlab, it seems to only have the single quotes around it, which is normal for any other file. However, when I open it in notepad++, it seems to have '"' double quotes around everything. Is there a way to remove these double quotes in any other way? My code doesn't seem to do anything as seen here:
After using xlswrite to write the replacement cell-array to a .csv file, one appears corrupted. Any idea why?
So, my questions are:
Is there any way to remove the quotes in a more efficient manner or without rewriting to a csv?
and
What exactly is causing the corruption in the xlswrite function? The variable replacement seems perfectly normal.
Thanks in advance!
Regarding the "corrupted" file. That's not a corrupted file, that's an xls file (not xlsx). You could verify this opening the text file in a hex editor to compare the signature. This happens when you chose no file extension or ask excel to write a file which can't be encoded into csv. I assume it's some character which causes the problems, try to isolate the critical line writing only parts of the cell.
Regarding your warning, not having the actual input I could only guess what's wrong. Again, I can only give some advices to debug the problem yourself. Run this code:
lastwarn('')
for m = 1:currentsize(1)
for n = 1:currentsize(2)
replacement{m,n} = strrep(current{m,n}, '"', '');
if ~isempty(lastwarn)
keyboard
lastwarn('')
end
end
end
This will launch the debugger when a warning is raised, allowing you to check the content of current{m,n}
It is mentionned in the documentation of strrep that :
The strrep function does not find empty strings for replacement. That is, when origStr and oldSubstr both contain the empty string (''), strrep does not replace '' with the contents of newSubstr.
You can use this user function substr like this :
for m = 1:currentsize(1)
for n = 1:currentsize(2)
replacement{m,n} = substr(current{m,n}, 2, -1);
end
end
Please use xlswrite function like this :
[status,message] = xlswrite(___)
and check the status if it is zero, that means the function did not succeed and an error message is generated in message as string.
GCC version 4.6
The Problem: To find a way to feed in parameters to the executable, say a.out, from the command line - more specifically feed in an array of double precision numbers.
Attempt: Using the READ(*,*) command, which is older in the standard:
Program test.f -
PROGRAM MAIN
REAL(8) :: A,B
READ(*,*) A,B
PRINT*, A+B, COMMAND_ARGUMENT_COUNT()
END PROGRAM MAIN
The execution -
$ gfortran test.f
$ ./a.out 3.D0 1.D0
This did not work. On a bit of soul-searching, found that
$./a.out
3.d0,1.d0
4.0000000000000000 0
does work, but the second line is an input prompt, and the objective of getting this done in one-line is not achieved. Also the COMMAND_ARGUMENT_COUNT() shows that the numbers fed into the input prompt don't really count as 'command line arguments', unlike PERL.
If you want to get the arguments fed to your program on the command line, use the (since Fortran 2003) standard intrinsic subroutine GET_COMMAND_ARGUMENT. Something like this might work
PROGRAM MAIN
REAL(8) :: A,B
integer :: num_args, ix
character(len=12), dimension(:), allocatable :: args
num_args = command_argument_count()
allocate(args(num_args)) ! I've omitted checking the return status of the allocation
do ix = 1, num_args
call get_command_argument(ix,args(ix))
! now parse the argument as you wish
end do
PRINT*, A+B, COMMAND_ARGUMENT_COUNT()
END PROGRAM MAIN
Note:
The second argument to the subroutine get_command_argument is a character variable which you'll have to parse to turn into a real (or whatever). Note also that I've allowed only 12 characters in each element of the args array, you may want to fiddle around with that.
As you've already figured out read isn't used for reading command line arguments in Fortran programs.
Since you want to read an array of real numbers, you might be better off using the approach you've already figured out, that is reading them from the terminal after the program has started, it's up to you.
The easiest way is to use a library. There is FLAP or f90getopt available. Both are open source and licensed under free licenses.
The latter is written by Mark Gates and me, just one module and can be learned in minutes but contains all what is needed to parse GNU- and POSIX-like command-line options. The first is more sophisticated and can be used even in closed-source projects. Check them out.
Furthermore libraries at https://fortranwiki.org/fortran/show/Command-line+arguments
What READ (*,*) does is that it reads from the standard input. For example, the characters entered using the keyboard.
As the question shows COMMAND_ARGUMENT_COUNT() can be used to get the number of the command line arguments.
The accepted answer by High Performance Mark show how to retrieve the individual command line arguments separated by blanks as individual character strings using GET_COMMAND_ARGUMENT(). One can also get the whole command line using GET_COMMAND(). One then has to somehow parse that character-based information into the data in your program.
I very simple cases you just need the program requires, for example, two numbers, so you read one number from arg 1 and another form arg 2. That is simple. Or you can read a triplet of numbers from a single argument if they are comma-separated like 1,2,3 using a simple read(arg,*) nums(1:3).
For general complicated command line parsing one uses libraries such as those mentioned in the answer by Hani. You have set them up so that the library knows the expected syntax of the command line arguments and the data it should fill with the values.
There is a middle ground, that is still relatively simple, but one already have multiple arguments, that correspond to Fortran variables in the program, that may or may not be present. In that case one can use the namelist for the syntax and for the parsing.
Here is an example, the man point is the namelist /cmd/ name, point, flag:
implicit none
real :: point(3)
logical :: flag
character(256) :: name
character(1024) :: command_line
call read_command_line
call parse_command_line
print *, point
print *, "'",trim(name),"'"
print *, flag
contains
subroutine read_command_line
integer :: exenamelength
integer :: io, io2
command_line = ""
call get_command(command = command_line,status = io)
if (io==0) then
call get_command_argument(0,length = exenamelength,status = io2)
if (io2==0) then
command_line = "&cmd "//adjustl(trim(command_line(exenamelength+1:)))//" /"
else
command_line = "&cmd "//adjustl(trim(command_line))//" /"
end if
else
write(*,*) io,"Error getting command line."
end if
end subroutine
subroutine parse_command_line
character(256) :: msg
namelist /cmd/ name, point, flag
integer :: io
if (len_trim(command_line)>0) then
msg = ''
read(command_line,nml = cmd,iostat = io,iomsg = msg)
if (io/=0) then
error stop "Error parsing the command line or cmd.conf " // msg
end if
end if
end subroutine
end
Usage in bash:
> ./command flag=T name=\"data.txt\" point=1.0,2.0,3.0
1.00000000 2.00000000 3.00000000
'data.txt'
T
or
> ./command flag=T name='"data.txt"' point=1.0,2.0,3.0
1.00000000 2.00000000 3.00000000
'data.txt'
T
Escaping the quotes for the string is unfortunately necessary, because bash eats the first quotes.