The gperf info pages claims that if you specify -l then
The keywords in the input file may contain NUL bytes, written in
string syntax as \000 or \x00, and the code generated by gperf will
treat NUL like any other byte
However when I run this input file through gperf -L C++ -l:
foo
\000bar\000
\x00baz\x00
bat
I get:
<snip>
static const char * wordlist[] =
{
"", "", "",
"foo",
"", "", "", "",
"bat",
"", "",
"\\x00baz\\x00",
"", "", "", "",
"\\000bar\\000"
};
<snip>
Which looks like it's treating the \000 and \x00 as literal values rather than null bytes.
How can I use correctly specify null bytes in my gperf strings?
You find a more precise documentation of the input syntax in section "Format for Keyword Entries":
It can be given in two ways: as a simple name, i.e., without surrounding
string quotation marks, or as a string enclosed in double-quotes, in C syntax,
possibly with backslash escapes like \" or \234 or \xa8.
And in gperf's test suite, you find an example:
"\x00\x45\x00\x6E\x00\x67\x00\x6C\x00\x69\x00\x73\x00\x68", "English", "en_GB.UTF-8"
Related
I have a string that I want to insert dynamically a variable. Ex;
$tag = '{"number" = "5", "application" = "test","color" = "blue", "class" = "Java"}'
I want to accomplish:
$mynumber= 2
$tag = '{"number" = "$($mynumber)", "application" = "test","color" = "blue", "class" = "Java"}'
What I want is to have the variable inserted on the string, But it is not going through. I guess the '' sets all as a string. Any recomendations on how should I approach this?
thanks!
powershell test and trial and error. Also Google.
The reason your current attempt doesn't work is that single-quoted (') string literals in PowerShell are verbatim strings - no attempt will be made at expanding subexpression pipelines or variable expressions.
If you want an expandable string literal without having to escape all the double-quotes (") contained in the string itself, use a here-string:
$mynumber = 2
$tag = #"
{"number" = "$($mynumber)", "application" = "test","color" = "blue", "class" = "Java"}
"#
To add to Mathias' helpful answer:
Mistakenly expecting string interpolation inside '...' strings (as opposed to inside "...") has come up many times before, and questions such as yours are often closed as a duplicate of this post.
However, your question is worth answering separately, because:
Your use case introduces a follow-up problem, namely that embedded " characters cannot be used as-is inside "...".
More generally, the linked post is in the context of argument-passing, where additional rules apply.
Note: Some links below are to the relevant sections of the conceptual about_Quoting_Rules help topic.
In PowerShell:
only "..." strings (double-quoted, called expandable strings) perform string interpolation, i.e. expansion of variable values (e.g. "... $var" and subexpressions (e.g., "... $($var.Prop)")
not '...' strings (single-quoted, called verbatim strings), whose values are used verbatim (literally).
With "...", if the string value itself contains " chars.:
either escape them as `" or ""
E.g., with `"; note that while use of $(...), the subexpression operator never hurts (e.g. $($mynumber)), it isn't necessary with stand-alone variable references such as $mynumber:
$mynumber= 2
$tag = "{`"number`" = `"$mynumber`", `"application`" = `"test`",`"color`" = `"blue`", `"class`" = `"Java`"}"
Similarly, if you want to selectively suppress string interpolation, escape $ as `$
# Note the ` before the first $mynumber.
# -> '$mynumber = 2'
$mynumber = 2; "`$mynumber` = $mynumber"
See the conceptual about_Special_Characters help topic for info on escaping and escape sequences.
If you need to embed ' inside '...', use '', or use a (single-quoted) here-string (see next).
or use a double-quoted here-string instead (#"<newline>...<newline>"#):
See Mathias' answer, but generally note the strict, multiline syntax of here-strings:
Nothing (except whitespace) must follow the opening delimiter on the same line (#" / #')
The closing delimiter ("# / '#) must be at the very start of the line - not even whitespace may come before it.
Related answers:
Overview of PowerShell's expandable strings
Overview of all forms of string literals in PowerShell
When passing strings as command arguments, they are situationally implicitly treated like expandable strings (i.e. as if they were "..."-enclosed); e.g.
Write-Output $HOME\projects - see this answer.
Alternatives to string interpolation:
Situationally, other approaches to constructing a string dynamically can be useful:
Use a (verbatim) template string with placeholders, with -f, the format operator:
$mynumber= 2
# {0} is the placeholder for the first RHS operand ({1} for the 2nd, ...)
'"number" = "{0}", ...' -f $mynumber # -> "number" = "2", ...
Use simple string concatenation with the + operator:
$mynumber= 2
'"number" = "' + $mynumber + '", ...' # -> "number" = "2", ...
I have a string that I want to insert dynamically a variable. Ex;
$tag = '{"number" = "5", "application" = "test","color" = "blue", "class" = "Java"}'
I want to accomplish:
$mynumber= 2
$tag = '{"number" = "$($mynumber)", "application" = "test","color" = "blue", "class" = "Java"}'
What I want is to have the variable inserted on the string, But it is not going through. I guess the '' sets all as a string. Any recomendations on how should I approach this?
thanks!
powershell test and trial and error. Also Google.
The reason your current attempt doesn't work is that single-quoted (') string literals in PowerShell are verbatim strings - no attempt will be made at expanding subexpression pipelines or variable expressions.
If you want an expandable string literal without having to escape all the double-quotes (") contained in the string itself, use a here-string:
$mynumber = 2
$tag = #"
{"number" = "$($mynumber)", "application" = "test","color" = "blue", "class" = "Java"}
"#
To add to Mathias' helpful answer:
Mistakenly expecting string interpolation inside '...' strings (as opposed to inside "...") has come up many times before, and questions such as yours are often closed as a duplicate of this post.
However, your question is worth answering separately, because:
Your use case introduces a follow-up problem, namely that embedded " characters cannot be used as-is inside "...".
More generally, the linked post is in the context of argument-passing, where additional rules apply.
Note: Some links below are to the relevant sections of the conceptual about_Quoting_Rules help topic.
In PowerShell:
only "..." strings (double-quoted, called expandable strings) perform string interpolation, i.e. expansion of variable values (e.g. "... $var" and subexpressions (e.g., "... $($var.Prop)")
not '...' strings (single-quoted, called verbatim strings), whose values are used verbatim (literally).
With "...", if the string value itself contains " chars.:
either escape them as `" or ""
E.g., with `"; note that while use of $(...), the subexpression operator never hurts (e.g. $($mynumber)), it isn't necessary with stand-alone variable references such as $mynumber:
$mynumber= 2
$tag = "{`"number`" = `"$mynumber`", `"application`" = `"test`",`"color`" = `"blue`", `"class`" = `"Java`"}"
Similarly, if you want to selectively suppress string interpolation, escape $ as `$
# Note the ` before the first $mynumber.
# -> '$mynumber = 2'
$mynumber = 2; "`$mynumber` = $mynumber"
See the conceptual about_Special_Characters help topic for info on escaping and escape sequences.
If you need to embed ' inside '...', use '', or use a (single-quoted) here-string (see next).
or use a double-quoted here-string instead (#"<newline>...<newline>"#):
See Mathias' answer, but generally note the strict, multiline syntax of here-strings:
Nothing (except whitespace) must follow the opening delimiter on the same line (#" / #')
The closing delimiter ("# / '#) must be at the very start of the line - not even whitespace may come before it.
Related answers:
Overview of PowerShell's expandable strings
Overview of all forms of string literals in PowerShell
When passing strings as command arguments, they are situationally implicitly treated like expandable strings (i.e. as if they were "..."-enclosed); e.g.
Write-Output $HOME\projects - see this answer.
Alternatives to string interpolation:
Situationally, other approaches to constructing a string dynamically can be useful:
Use a (verbatim) template string with placeholders, with -f, the format operator:
$mynumber= 2
# {0} is the placeholder for the first RHS operand ({1} for the 2nd, ...)
'"number" = "{0}", ...' -f $mynumber # -> "number" = "2", ...
Use simple string concatenation with the + operator:
$mynumber= 2
'"number" = "' + $mynumber + '", ...' # -> "number" = "2", ...
Due to the document of glib.string.escape()
Escapes the special characters '\b', '\f', '\n', '\r', '\t', '\v', '\' and '"' in the string source by inserting a '\' before them.
Additionally all characters in the range 0x01-0x1F (everything below SPACE) and in the range 0x7F-0xFF (all non-ASCII chars) are replaced with a '\' followed by their octal representation. Characters supplied in exceptions are not escaped.
Now I want not eacape "0x7F-0xFF" characters. How to write the exceptions part?
my example code no work.
shellcmd = "bash -c \""+file.get_string(title,"List").escape("0x7F-0xFF")+"\"";
print("shellcmd: %s\n", shellcmd);
Process.spawn_command_line_sync (shellcmd,
out ls_stdout, out ls_stderr, out ls_status);
if(ls_status!=0){ list = ls_stderr.split("\n"); }
else{ list = ls_stdout.split("\n"); }
this works.
shellcmd = "bash -c \""+file.get_string(title,"Check").replace("\"","\\\"")+"\"";
You actually have to put the characters 0x7f to 0xff in the exceptions argument. So something like:
shellcmd = "bash -c \""+file.get_string(title,"List").escape("\x7F\x80\x81\x82…\xfe\xff")+"\"";
You would need to list them all manually.
Looking more generally at your code, you seem to be constructing a command to run. This is a very bad idea and you should never do it. It is wide open to code injection. Use Process.spawn_sync() and pass it an argument vector instead.
I want to write a snippet for Debugging in TYPO3.
This is my Snippet-Code in php.json file:
"TYPO3 Extbase DebuggerUtility": {
"prefix": "ee",
"body": [
"\\TYPO3\\CMS\\Extbase\\Utility\\DebuggerUtility::var_dump($1,'$1');",
"$0"
],
"description": "TYPO3 Extbase DebuggerUtility"
},
If I want to debug something liket this : $this->settings['key'] I get this code:
\TYPO3\CMS\Extbase\Utility\DebuggerUtility::var_dump($this->settings['key'],'$this->settings['key']');
But it should looks like this
\TYPO3\CMS\Extbase\Utility\DebuggerUtility::var_dump($this->settings['key'],'$this->settings[\'key\']');
With escaped ' in the second part of that snippet.
EDIT
Thank you, but I think you missunderstood the question.
I don't want to escape a static character. I want to use the snippet and when I type the first $1-content it should be $this->settings['someKey'] but the second $1 (which is near the same) should automatically escape the ' chars I write, that I don't do this manually by hand.
So if i type '
first $1: ' second $1: \' that my Debug looks like this
Debug:
$this->settings['someKey']
contentOfsomeKey
I I don't escape the ' signs inside the "title of the debug" it breaks the string because ' wraps the debug-title.
In other words: I want to escape the content of the second $1 variable not the variable or the '-wrap in the snippet.
I hope I could clarify my issue.
If you want escape characters \ in your output you need to insert escaped escape characters: \\ this should result in single escape characters.
You might need an additional escape character if the following character needs an additional escaping: one backslash before quote \' = \\+ \' = \\\'
`
I have a string, "Shirt base price: $15"
(The string has the spaces in between "Shirt" and "base."
How can I pull out just the "Shirt" phrase of this string?
You can split the string at spaces to get the first word in it.
String firstWord = str.split("\\s+")[0];
The split method takes a regular expression to split around, the \\s+ argument tells it to split the string around sequences of one or more whitespace characters, and the [0] gets the first index of the array that was returned.