I use JSLint and have a huge library of code that is 100% JSLint clean. As of 1.20.2011, JSLint reports errors whitespacing errors on every var statement. Take, for example, this (now hollowed out) function:
var dateStrFromTimestamp;
dateStrFromTimestamp = function (t) {
"use strict";
var a, d;
d = new Date(t * 1000);
a = [];
};
JSLint reports:
Problem at line 1 character 5: Expected 'dateStrFromTimestamp' at column 3, not column 5.
var dateStrFromTimestamp;
Problem at line 4 character 7: Expected 'a' at column 5, not column 7.
var a, d;
How am I supposed to write my code? If I follow the recommendation, I'd have to remove the whitespace after the keyword "var" -- but that can't be. So, is the current version of JSLint buggy? Or am I currently blind to something obvious?
Looks like he's fixed it. I continued getting the problem, then did a Shift+refresh to clear his JS file from my cache, and that seemed to fix it I think.
This is probably because you mixed tabs ans spaces, and JSLint supposes that a tab is the equivalent of 4 spaces.
Related
Is there an efficient algorithm for finding broken parenthesis in a block of text for the purpose of intellisense error highlighting?
For instance:
function f() {
var a = [1, 2, 3];
if ((a[1] < 1) || (a[0] > 2)) {
console.log((a + 5).toString());
}
}
Where any (, ), [, ], {, or } character might be dropped or adding in correctly and the correct issue might be highlighted, for instance spotting the specific statement, function, conditional, etc level item causing the issue?
The algorithm is not difficult:
Have a stack of characters
For each character in the code:
If it's an opening bracket, push it onto the stack
If it's a closing bracket, pop one char from the stack, both must match
At the end the stack must be empty
Then you could maybe highlight the unmatched bracket(s).
I think that one way of approaching your problem is to validate the matching bracket groups. This may be achieved using the regular expression - see: http://blog.stevenlevithan.com/archives/javascript-match-nested of Steven Levithan.
I've got a file with syntactically correct Lua 5.1 source code.
I've got a position (line and character offset) inside that file.
I need to get an offset in bytes to the closing parenthesis of the innermost function() body that contains that position (or figure out that the position belongs to the main chunk of the file).
I.e.:
local function foo()
^ result
print("bar")
^ input
end
local foo = function()
^ result
print("bar")
^ input
end
local foo = function()
return function()
^ result
print("bar")
^ input
end
end
...And so on.
How do I do that robustly?
EDIT: My original answer did not take into account the "innermost" requirement. I've since taken that into account
To make things "robust," there are a few considerations.
First of all, it's important that you skip over string and comment contents, to avoid incorrect output in situations like:
foo = function()
print(" function() ")
-- function()
print("bar")
^ input
end
This can be somewhat difficult, considering Lua's nested string and comment syntax. Consider, for example, a situation where the input begins in a nested string or comment:
foo = function()
print([[
bar = function()
print("baz")
^ input
end
]])
end
Consequently, if you want a completely robust system, it is not acceptable to only parse backwards until you hit the end of a function parameter list, because you may not have parsed backwards far enough to reach a [[ which would invalidate your match. It is therefore necessary to parse the entire file up to your position (unless you're okay with incorrect matches in these weird situations. If this is an editor plugin, these "incorrect" results may actually be desirable, because they would allow you to edit lua code which is stored in string literal form inside other lua code using the same plugin).
Because the particular syntax that you're trying to match doesn't have any kind of "nesting", a full-blown parser isn't needed. You will need to maintain a stack, however, to keep track of scope. With that in mind, all you need to do is step through the source file character-by-character from the beginning, applying the following logic:
Every time a " or ' is encountered, ignore the characters up to the closing " or '. Be careful to handle escapes like \" and \\
Every time a -- is encountered, ignore the characters up to the closing newline for the comment. Be careful to only do this if the comment is not a multiline comment.
Every time a multiline string opening symbol is encountered (such as [[, [=[, etc), or a multiline comment symbol is encountered (such as --[[ or --[=[, etc) ignore the characters up until the closing square brackets with the proper number of matching equals signs between them.
When a word boundary is encountered check to see if the characters after it could begin a block which ends with an end (for example, if, while, for, function, etc. DO NOT include repeat). If so, push the position on the scope stack. A "word boundary" in this case is any character which could not be used a lua identifier (this is to prevent matches in cases like abcfunction()). The beginning of the file is also considered a word boundary.
If a word boundary is encountered and it is followed by end, pop the top element of the stack. If the stack has no elements, complain about a syntax error.
When you finally step forward and reach your "input" position, pop elements from the stack until you find a function scope. Step forward from that position to the next ), ignoring )'s in comments (which could theoretically be found in an argument list if it spans multiple lines or contains inline --[[ ]] comments). That position is your result.
This should handle every case, including situations where the function syntactic sugar is used, like
function foo()
print("bar")
end
which you did not include in your example but which I imagine you still want to match.
I need to remove all \text generated by TeXForm in Mathematica.
What I am doing now is this:
MyTeXForm[a_]:=StringReplace[ToString[TeXForm[a]], "\\text" -> ""]
But the result keeps the braces, for example:
for a=fx,
the result of TeXForm[a] is \text{fx}
the result of MyTeXForm[a] is {fx}
But what I would like is it to be just fx
You should be able to use string patterns. Based on http://reference.wolfram.com/mathematica/tutorial/StringPatterns.html, something like the following should work:
MyTeXForm[a_]:=StringReplace[ToString[TeXForm[a]], "\\text{"~~s___~~"}"->s]
I don't have Mathematica handy right now, but this should say 'Match "\text{" followed by zero or more characters that are stored in the variable s, followed by "}", then replace all of that with whatever is stored in s.'
UPDATE:
The above works in the simplest case of there being a single "\text{...}" element, but the pattern s___ is greedy, so on input a+bb+xx+y, which Mathematica's TeXForm renders as "a+\text{bb}+\text{xx}+y", it matches everything between the first "\text{" and last "}" --- so, "bb}+\text{xx" --- leading to the output
In[1]:= MyTeXForm[a+bb+xx+y]
Out[1]= a+bb}+\text{xx+y
A fix for this is to wrap the pattern with Shortest[], leading to a second definition
In[2]:= MyTeXForm2[a_] := StringReplace[
ToString[TeXForm[a]],
Shortest["\\text{" ~~ s___ ~~ "}"] -> s
]
which yields the output
In[3]:= MyTeXForm2[a+bb+xx+y]
Out[3]= a+bb+xx+y
as desired.
Unfortunately this still won't work when the text itself contains a closing brace. For example, the input f["a}b","c}d"] (for some reason...) would give
In[4]:= MyTeXForm2[f["a}b","c}d"]]
Out[4]= f(a$\$b},c$\$d})
instead of "f(a$\}$b,c$\}$d)", which would be the proper processing of the TeXForm output "f(\text{a$\}$b},\text{c$\}$d})".
This is what I did (works fine for me):
MyTeXForm[a_] := ToString[ToExpression[StringReplace[ToString[TeXForm[a]], "\\text" -> ""]][[1]]]
This is a really late reply, but I just came up against the same issue and discovered a simple solution. Put a space between the variables in the Mathematica expression that you wish to convert using TexForm.
For the original poster's example, the following code works great:
a=f x
TeXForm[a]
The output is as desired: f x
Since LaTeX will ignore that space in math mode, things will format correctly.
(As an aside, I was having the same issue with subscripted expressions that have two side-by-side variables in the subscript. Inserting a space between them solved the issue.)
Why JSLint is producing this kind of warning
Problem at line xxx character yyy: Expected 'X' to have an indentation at xx instead at yyy.
Why does it matter to have a different space formatting?
Well, since you didn't show us the line, we can only guess, but it's probably something like this.
if(someCondition)
DoThis();
DoThat();
Since it would expect the indenting to be:
if(someCondition)
DoThis();
DoThat();
It thinks you may want it to be:
if(someCondition)
{
DoThis();
DoThat();
}
You have indented something that shouldn't be indented, or shouldn't be indented as much.
This often happens after declaring several variables:
var foo,
bar;
baz = something;
or with if statements as #James Curran mentioned. Just go to line xxx and see if something is indented that shouldn't be. If you can't find it, post the section og the code in the question and let us have a look.
As James points out, it's likely a spacing issue.
var spam = 3;
if (3 === spam) {
spam = 4;
}
... gives me Expected 'spam' at column 5, not column 1.
If whitespace isn't something you want JSLint to check (and it generally isn't for me), you have two choices to turn off "sloppy whitespace" checks. On the site (or in your tool of choice), you can check "white", or you can add a directive at the top of your file, like this:
/*jslint white:true*/
var spam = 3;
if (3 === spam) {
spam = 4;
}
Now I get a clean bill o' lint.
I've been given a large file with a funny CSV format to parse into a database.
The separator character is a semicolon (;). If one of the fields contains a semicolon it is "escaped" by wrapping it in doublequotes, like this ";".
I have been assured that there will never be two adjacent fields with trailing/ leading doublequotes, so this format should technically be ok.
Now, for parsing it in VBScript I was thinking of
Replacing each instance of ";" with a GUID,
Splitting the line into an array by semicolon,
Running back through the array, replacing the GUIDs with ";"
It seems to be the quickest way. Is there a better way? I guess I could use substrings but this method seems to be acceptable...
Your method sounds fine with the caveat that there's absolutely no possibility that your GUID will occur in the text itself.
On approach I've used for this type of data before is to just split on the semi-colons regardless then, if two adjacent fields end and start with a quote, combine them.
For example:
Pax;is;a;good;guy";" so;says;his;wife.
becomes:
0 Pax
1 is
2 a
3 good
4 guy"
5 " so
6 says
7 his
8 wife.
Then, when you discover that fields 4 and 5 end and start (respectively) with a quote, you combine them by replacing the field 4 closing quote with a semicolon and removing the field 5 opening quote (and joining them of course).
0 Pax
1 is
2 a
3 good
4 guy; so
5 says
6 his
7 wife.
In pseudo-code, given:
input: A string, first character is input[0]; last
character is input[length]. Further, assume one dummy
character, input[length+1]. It can be anything except
; and ". This string is one line of the "CSV" file.
length: positive integer, number of characters in input
Do this:
set start = 0
if input[0] = ';':
you have a blank field in the beginning; do whatever with it
set start = 2
endif
for each c between 1 and length:
next iteration unless string[c] = ';'
if input[c-1] ≠ '"' or input[c+1] ≠ '"': // test for escape sequence ";"
found field consting of half-open range [start,c); do whatever
with it. Note that in the case of empty fields, start≥c, leaving
an empty range
set start = c+1
endif
end foreach
Untested, of course. Debugging code like this is always fun….
The special case of input[0] is to make sure we don't ever look at input[-1]. If you can make input[-1] safe, then you can get rid of that special case. You can also put a dummy character in input[0] and then start your data—and your parsing—from input[1].
One option would be to find instances of the regex:
[^"];[^"]
and then break the string apart with substring:
List<string> ret = new List<string>();
Regex r = new Regex(#"[^""];[^""]");
Match m;
while((m = r.Match(line)).Success)
{
ret.Add(line.Substring(0,m.Index + 1);
line = line.Substring(m.Index + 2);
}
(Sorry about the C#, I don't known VBScript)
Using quotes is normal for .csv files. If you have quotes in the field then you may see opening and closing and the embedded quote all strung together two or three in a row.
If you're using SQL Server you could try using T-SQL to handle everything for you.
SELECT * INTO MyTable FROM OPENDATASOURCE('Microsoft.JET.OLEDB.4.0',
'Data Source=F:\MyDirectory;Extended Properties="text;HDR=No"')...
[MyCsvFile#csv]
That will create and populate "MyTable". Read more on this subject here on SO.
I would recommend using RegEx to break up the strings.
Find every ';' that is not a part of
";" and change it to something else
that does not appear in your fields.
Then go through and replace ";" with ;
Now you have your fields with the correct data.
Most importers can swap out separator characters pretty easily.
This is basically your GUID idea. Just make sure the GUID is unique to your file before you start and you will be fine. I tend to start using 'Z'. After enough 'Z's, you will be unique (sometimes as few as 1-3 will do).
Jacob