diff options
Diffstat (limited to 'doc/string.n')
| -rw-r--r-- | doc/string.n | 258 |
1 files changed, 171 insertions, 87 deletions
diff --git a/doc/string.n b/doc/string.n index 7e427ab..33780ff 100644 --- a/doc/string.n +++ b/doc/string.n @@ -14,13 +14,28 @@ string \- Manipulate strings .SH SYNOPSIS \fBstring \fIoption arg \fR?\fIarg ...?\fR .BE - .SH DESCRIPTION .PP Performs one of several string operations, depending on \fIoption\fR. The legal \fIoption\fRs (which may be abbreviated) are: .TP -\fBstring compare\fR ?\fB\-nocase\fR? ?\fB\-length int\fR? \fIstring1 string2\fR +\fBstring cat\fR ?\fIstring1\fR? ?\fIstring2...\fR? +.VS 8.6.2 +Concatenate the given \fIstring\fRs just like placing them directly +next to each other and return the resulting compound string. If no +\fIstring\fRs are present, the result is an empty string. +.RS +.PP +This primitive is occasionally handier than juxtaposition of strings +when mixed quoting is wanted, or when the aim is to return the result +of a concatenation without resorting to \fBreturn\fR \fB\-level 0\fR, +and is more efficient than building a list of arguments and using +\fBjoin\fR with an empty join string. +.RE +.VE +.TP +\fBstring compare\fR ?\fB\-nocase\fR? ?\fB\-length\fI length\fR? \fIstring1 string2\fR +. Perform a character-by-character comparison of strings \fIstring1\fR and \fIstring2\fR. Returns \-1, 0, or 1, depending on whether \fIstring1\fR is lexicographically less than, equal to, or greater @@ -29,7 +44,8 @@ first \fIlength\fR characters are used in the comparison. If \fB\-length\fR is negative, it is ignored. If \fB\-nocase\fR is specified, then the strings are compared in a case-insensitive manner. .TP -\fBstring equal\fR ?\fB\-nocase\fR? ?\fB\-length int\fR? \fIstring1 string2\fR +\fBstring equal\fR ?\fB\-nocase\fR? ?\fB\-length\fI length\fR? \fIstring1 string2\fR +. Perform a character-by-character comparison of strings \fIstring1\fR and \fIstring2\fR. Returns 1 if \fIstring1\fR and \fIstring2\fR are identical, or 0 when not. If \fB\-length\fR is specified, then only @@ -38,80 +54,43 @@ the first \fIlength\fR characters are used in the comparison. If specified, then the strings are compared in a case-insensitive manner. .TP \fBstring first \fIneedleString haystackString\fR ?\fIstartIndex\fR? +. Search \fIhaystackString\fR for a sequence of characters that exactly match the characters in \fIneedleString\fR. If found, return the index of the first character in the first such match within \fIhaystackString\fR. If not found, return \-1. If \fIstartIndex\fR is specified (in any of the -forms accepted by the \fBindex\fR method), then the search is +forms described in \fBSTRING INDICES\fR), then the search is constrained to start with the character in \fIhaystackString\fR specified by the index. For example, .RS +.PP .CS \fBstring first a 0a23456789abcdef 5\fR .CE +.PP will return \fB10\fR, but +.PP .CS \fBstring first a 0123456789abcdef 11\fR .CE +.PP will return \fB\-1\fR. .RE .TP \fBstring index \fIstring charIndex\fR +. Returns the \fIcharIndex\fR'th character of the \fIstring\fR argument. A \fIcharIndex\fR of 0 corresponds to the first character of the -string. \fIcharIndex\fR may be specified as follows: -.VS 8.5 +string. \fIcharIndex\fR may be specified as described in the +\fBSTRING INDICES\fR section. .RS -.IP \fIinteger\fR 10 -For any index value that passes \fBstring is integer -strict\fR, -the char specified at this integral index -(e.g. \fB2\fR would refer to the -.QW c -in -.QW abcd ). -.IP \fBend\fR 10 -The last char of the string -(e.g. \fBend\fR would refer to the -.QW d -in -.QW abcd ). -.IP \fBend\fR\-\fIN\fR 10 -The last char of the string minus the specified integer offset \fIN\fR -(e.g. \fBend\fR\-1 would refer to the -.QW c -in -.QW abcd ). -.IP \fBend\fR+\fIN\fR 10 -The last char of the string plus the specified integer offset \fIN\fR -(e.g. \fBend\fR+\-1 would refer to the -.QW c -in -.QW abcd ). -.IP \fIM\fR+\fIN\fR 10 -The char specified at the integral index that is the sum of -integer values \fIM\fR and \fIN\fR -(e.g. \fB1+1\fR would refer to the -.QW c -in -.QW abcd ). -.IP \fIM\fR\-\fIN\fR 10 -The char specified at the integral index that is the difference of -integer values \fIM\fR and \fIN\fR -(e.g. \fB2\-1\fR would refer to the -.QW b -in -.QW abcd ). -.PP -In the specifications above, the integer value \fIM\fR contains no -trailing whitespace and the integer value \fIN\fR contains no -leading whitespace. .PP If \fIcharIndex\fR is less than 0 or greater than or equal to the length of the string then this command returns an empty string. .RE -.VE .TP \fBstring is \fIclass\fR ?\fB\-strict\fR? ?\fB\-failindex \fIvarname\fR? \fIstring\fR +. Returns 1 if \fIstring\fR is a valid member of the specified character class, otherwise returns 0. If \fB\-strict\fR is specified, then an empty string returns 0, otherwise an empty string will return 1 on @@ -139,6 +118,12 @@ outside of the [0\-9] range. Any of the valid forms for a double in Tcl, with optional surrounding whitespace. In case of under/overflow in the value, 0 is returned and the \fIvarname\fR will contain \-1. +.IP \fBentier\fR 12 +.VS 8.6 +Any of the valid string formats for an integer value of arbitrary size +in Tcl, with optional surrounding whitespace. The formats accepted are +exactly those accepted by the C routine \fBTcl_GetBignumFromObj\fR. +.VE .IP \fBfalse\fR 12 Any of the forms allowed to \fBTcl_GetBoolean\fR where the value is false. @@ -161,19 +146,18 @@ Any Unicode printing character, including space. .IP \fBpunct\fR 12 Any Unicode punctuation character. .IP \fBspace\fR 12 -Any Unicode whitespace character or mongolian vowel separator (U+180e), -but not NEL/Next Line (U+0085). +Any Unicode whitespace character, mongolian vowel separator +(U+180e), zero width space (U+200b), word joiner (U+2060) or +zero width no-break space (U+feff) (=BOM). .IP \fBtrue\fR 12 Any of the forms allowed to \fBTcl_GetBoolean\fR where the value is true. .IP \fBupper\fR 12 Any upper case alphabet character in the Unicode character set. -.VS 8.5 .IP \fBwideinteger\fR 12 Any of the valid forms for a wide integer in Tcl, with optional surrounding whitespace. In case of under/overflow in the value, 0 is returned and the \fIvarname\fR will contain \-1. -.VE 8.5 .IP \fBwordchar\fR 12 Any Unicode word character. That is any alphanumeric character, and any Unicode connector punctuation characters (e.g. underscore). @@ -186,32 +170,39 @@ function will return 0, then the \fIvarname\fR will always be set to .RE .TP \fBstring last \fIneedleString haystackString\fR ?\fIlastIndex\fR? +. Search \fIhaystackString\fR for a sequence of characters that exactly match the characters in \fIneedleString\fR. If found, return the index of the first character in the last such match within \fIhaystackString\fR. If there is no match, then return \-1. If \fIlastIndex\fR is specified (in any -of the forms accepted by the \fBindex\fR method), then only the +of the forms described in \fBSTRING INDICES\fR), then only the characters in \fIhaystackString\fR at or before the specified \fIlastIndex\fR will be considered by the search. For example, .RS +.PP .CS \fBstring last a 0a23456789abcdef 15\fR .CE +.PP will return \fB10\fR, but +.PP .CS \fBstring last a 0a23456789abcdef 9\fR .CE +.PP will return \fB1\fR. .RE .TP \fBstring length \fIstring\fR +. Returns a decimal string giving the number of characters in \fIstring\fR. Note that this is not necessarily the same as the -number of bytes used to store the string. If the object is a -ByteArray object (such as those returned from reading a binary encoded -channel), then this will return the actual byte length of the object. +number of bytes used to store the string. If the value is a +byte array value (such as those returned from reading a binary encoded +channel), then this will return the actual byte length of the value. .TP \fBstring map\fR ?\fB\-nocase\fR? \fImapping string\fR +. Replaces substrings in \fIstring\fR based on the key-value pairs in \fImapping\fR. \fImapping\fR is a list of \fIkey value key value ...\fR as in the form returned by \fBarray get\fR. Each instance of a @@ -223,21 +214,26 @@ appearing first in the list will be checked first, and so on. \fIstring\fR is only iterated over once, so earlier key replacements will have no affect for later key matches. For example, .RS +.PP .CS \fBstring map {abc 1 ab 2 a 3 1 0} 1abcaababcabababc\fR .CE +.PP will return the string \fB01321221\fR. .PP Note that if an earlier \fIkey\fR is a prefix of a later one, it will completely mask the later one. So if the previous example is reordered like this, +.PP .CS \fBstring map {1 0 ab 2 a 3 abc 1} 1abcaababcabababc\fR .CE +.PP it will return the string \fB02c322c222c\fR. .RE .TP \fBstring match\fR ?\fB\-nocase\fR? \fIpattern\fR \fIstring\fR +. See if \fIpattern\fR matches \fIstring\fR; return 1 if it does, 0 if it does not. If \fB\-nocase\fR is specified, then the pattern attempts to match against the string in a case insensitive manner. For the two @@ -271,6 +267,7 @@ the special interpretation of the characters \fB*?[]\e\fR in .RE .TP \fBstring range \fIstring first last\fR +. Returns a range of consecutive characters from \fIstring\fR, starting with the character whose index is \fIfirst\fR and ending with the character whose index is \fIlast\fR. An index of 0 refers to the first @@ -282,9 +279,11 @@ equal to the length of the string then it is treated as if it were string is returned. .TP \fBstring repeat \fIstring count\fR +. Returns \fIstring\fR repeated \fIcount\fR number of times. .TP \fBstring replace \fIstring first last\fR ?\fInewstring\fR? +. Removes a range of consecutive characters from \fIstring\fR, starting with the character whose index is \fIfirst\fR and ending with the character whose index is \fIlast\fR. An index of 0 refers to the @@ -296,106 +295,191 @@ and if \fIlast\fR is greater than or equal to the length of the string then it is treated as if it were \fBend\fR. If \fIfirst\fR is greater than \fIlast\fR or the length of the initial string, or \fIlast\fR is less than 0, then the initial string is returned untouched. -.VS 8.5 .TP \fBstring reverse \fIstring\fR +. Returns a string that is the same length as \fIstring\fR but with its characters in the reverse order. -.VE 8.5 .TP \fBstring tolower \fIstring\fR ?\fIfirst\fR? ?\fIlast\fR? +. Returns a value equal to \fIstring\fR except that all upper (or title) case letters have been converted to lower case. If \fIfirst\fR is specified, it refers to the first char index in the string to start modifying. If \fIlast\fR is specified, it refers to the char index in the string to stop at (inclusive). \fIfirst\fR and \fIlast\fR may be -specified as for the \fBindex\fR method. +specified using the forms described in \fBSTRING INDICES\fR. .TP \fBstring totitle \fIstring\fR ?\fIfirst\fR? ?\fIlast\fR? +. Returns a value equal to \fIstring\fR except that the first character in \fIstring\fR is converted to its Unicode title case variant (or upper case if there is no title case variant) and the rest of the string is converted to lower case. If \fIfirst\fR is specified, it refers to the first char index in the string to start modifying. If \fIlast\fR is specified, it refers to the char index in the string to -stop at (inclusive). \fIfirst\fR and \fIlast\fR may be specified as -for the \fBindex\fR method. +stop at (inclusive). \fIfirst\fR and \fIlast\fR may be specified +using the forms described in \fBSTRING INDICES\fR. .TP \fBstring toupper \fIstring\fR ?\fIfirst\fR? ?\fIlast\fR? +. Returns a value equal to \fIstring\fR except that all lower (or title) case letters have been converted to upper case. If \fIfirst\fR is specified, it refers to the first char index in the string to start modifying. If \fIlast\fR is specified, it refers to the char index in the string to stop at (inclusive). \fIfirst\fR and \fIlast\fR may be -specified as for the \fBindex\fR method. +specified using the forms described in \fBSTRING INDICES\fR. .TP \fBstring trim \fIstring\fR ?\fIchars\fR? +. Returns a value equal to \fIstring\fR except that any leading or trailing characters present in the string given by \fIchars\fR are removed. If -\fIchars\fR is not specified then white space is removed (spaces, -tabs, newlines, and carriage returns). +\fIchars\fR is not specified then white space is removed (any character +for which \fBstring is space\fR returns 1, and "\0"). .TP \fBstring trimleft \fIstring\fR ?\fIchars\fR? +. Returns a value equal to \fIstring\fR except that any leading characters present in the string given by \fIchars\fR are removed. If -\fIchars\fR is not specified then white space is removed (spaces, -tabs, newlines, and carriage returns). +\fIchars\fR is not specified then white space is removed (any character +for which \fBstring is space\fR returns 1, and "\0"). .TP \fBstring trimright \fIstring\fR ?\fIchars\fR? +. Returns a value equal to \fIstring\fR except that any trailing characters present in the string given by \fIchars\fR are removed. If -\fIchars\fR is not specified then white space is removed (spaces, -tabs, newlines, and carriage returns). -.SH "OBSOLETE SUBCOMMANDS" +\fIchars\fR is not specified then white space is removed (any character +for which \fBstring is space\fR returns 1, and "\0"). +.SS "OBSOLETE SUBCOMMANDS" .PP These subcommands are currently supported, but are likely to go away in a future release as their functionality is either virtually never used or highly misleading. .TP \fBstring bytelength \fIstring\fR +. Returns a decimal string giving the number of bytes used to represent -\fIstring\fR in memory. Because UTF\-8 uses one to three bytes to -represent Unicode characters, the byte length will not be the same as -the character length in general. The cases where a script cares about -the byte length are rare. In almost all cases, you should use the +\fIstring\fR in memory when encoded as Tcl's internal modified UTF\-8; +Tcl may use other encodings for \fIstring\fR as well, and does not +guarantee to only use a single encoding for a particular \fIstring\fR. +Because UTF\-8 uses a variable number of bytes to represent Unicode +characters, the byte length will not be the same as the character +length in general. The cases where a script cares about the byte +length are rare. +.RS +.PP +In almost all cases, you should use the \fBstring length\fR operation (including determining the length of a -Tcl ByteArray object). Refer to the \fBTcl_NumUtfChars\fR manual +Tcl byte array value). Refer to the \fBTcl_NumUtfChars\fR manual entry for more details on the UTF\-8 representation. +.PP +Formally, the \fBstring bytelength\fR operation returns the content of +the \fIlength\fR field of the \fBTcl_Obj\fR structure, after calling +\fBTcl_GetString\fR to ensure that the \fIbytes\fR field is populated. +This is highly unlikely to be useful to Tcl scripts, as Tcl's internal +encoding is not strict UTF\-8, but rather a modified CESU\-8 with a +denormalized NUL (identical to that used in a number of places by +Java's serialization mechanism) to enable basic processing with +non-Unicode-aware C functions. As this representation should only +ever be used by Tcl's implementation, the number of bytes used to +store the representation is of very low value (except to C extension +code, which has direct access for the purpose of memory management, +etc.) +.PP +\fICompatibility note:\fR it is likely that this subcommand will be +withdrawn in a future version of Tcl. It is better to use the +\fBencoding convertto\fR command to convert a string to a known +encoding and then apply \fBstring length\fR to that. +.PP +.CS +\fBstring length\fR [encoding convertto utf-8 $theString] +.CE +.RE .TP \fBstring wordend \fIstring charIndex\fR +. Returns the index of the character just after the last one in the word containing character \fIcharIndex\fR of \fIstring\fR. \fIcharIndex\fR -may be specified as for the \fBindex\fR method. A word is +may be specified using the forms in \fBSTRING INDICES\fR. A word is considered to be any contiguous range of alphanumeric (Unicode letters or decimal digits) or underscore (Unicode connector punctuation) characters, or any single character other than these. .TP \fBstring wordstart \fIstring charIndex\fR -Returns the index of the first character in the word containing -character \fIcharIndex\fR of \fIstring\fR. \fIcharIndex\fR may be -specified as for the \fBindex\fR method. A word is considered to be any -contiguous range of alphanumeric (Unicode letters or decimal digits) -or underscore (Unicode connector punctuation) characters, or any -single character other than these. +. +Returns the index of the first character in the word containing character +\fIcharIndex\fR of \fIstring\fR. \fIcharIndex\fR may be specified using the +forms in \fBSTRING INDICES\fR. A word is considered to be any contiguous +range of alphanumeric (Unicode letters or decimal digits) or underscore +(Unicode connector punctuation) characters, or any single character other than +these. +.SH "STRING INDICES" +.PP +When referring to indices into a string (e.g., for \fBstring index\fR +or \fBstring range\fR) the following formats are supported: +.IP \fIinteger\fR 10 +For any index value that passes \fBstring is integer \-strict\fR, +the char specified at this integral index (e.g., \fB2\fR would refer to the +.QW c +in +.QW abcd ). +.IP \fBend\fR 10 +The last char of the string (e.g., \fBend\fR would refer to the +.QW d +in +.QW abcd ). +.IP \fBend\-\fIN\fR 10 +The last char of the string minus the specified integer offset \fIN\fR (e.g., +.QW \fBend\-1\fR +would refer to the +.QW c +in +.QW abcd ). +.IP \fBend+\fIN\fR 10 +The last char of the string plus the specified integer offset \fIN\fR (e.g., +.QW \fBend+\-1\fR +would refer to the +.QW c +in +.QW abcd ). +.IP \fIM\fB+\fIN\fR 10 +The char specified at the integral index that is the sum of +integer values \fIM\fR and \fIN\fR (e.g., +.QW \fB1+1\fR +would refer to the +.QW c +in +.QW abcd ). +.IP \fIM\fB\-\fIN\fR 10 +The char specified at the integral index that is the difference of +integer values \fIM\fR and \fIN\fR (e.g., +.QW \fB2\-1\fR +would refer to the +.QW b +in +.QW abcd ). +.PP +In the specifications above, the integer value \fIM\fR contains no +trailing whitespace and the integer value \fIN\fR contains no +leading whitespace. .SH EXAMPLE +.PP Test if the string in the variable \fIstring\fR is a proper non-empty prefix of the string \fBfoobar\fR. +.PP .CS set length [\fBstring length\fR $string] if {$length == 0} { set isPrefix 0 } else { - set isPrefix [\fBstring equal\fR -length $length $string "foobar"] + set isPrefix [\fBstring equal\fR \-length $length $string "foobar"] } .CE - .SH "SEE ALSO" expr(n), list(n) - .SH KEYWORDS case conversion, compare, index, match, pattern, string, word, equal, ctype, character, reverse - .\" Local Variables: .\" mode: nroff .\" End: |