diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/AddErrInfo.3 | 2 | ||||
| -rw-r--r-- | doc/GetInt.3 | 31 | ||||
| -rw-r--r-- | doc/Hash.3 | 2 | ||||
| -rw-r--r-- | doc/SetResult.3 | 2 | ||||
| -rw-r--r-- | doc/chan.n | 26 | ||||
| -rw-r--r-- | doc/concat.n | 1 | ||||
| -rw-r--r-- | doc/exec.n | 5 | ||||
| -rw-r--r-- | doc/expr.n | 389 | ||||
| -rw-r--r-- | doc/fcopy.n | 12 | ||||
| -rw-r--r-- | doc/file.n | 11 | ||||
| -rw-r--r-- | doc/http.n | 5 | ||||
| -rw-r--r-- | doc/proc.n | 28 | ||||
| -rw-r--r-- | doc/scan.n | 4 | ||||
| -rw-r--r-- | doc/variable.n | 7 | ||||
| -rw-r--r-- | doc/zlib.n | 18 |
15 files changed, 284 insertions, 259 deletions
diff --git a/doc/AddErrInfo.3 b/doc/AddErrInfo.3 index caba125..0b59349 100644 --- a/doc/AddErrInfo.3 +++ b/doc/AddErrInfo.3 @@ -119,7 +119,7 @@ retrieve the stack trace when script evaluation returns \fBTCL_ERROR\fR, like so: .PP .CS -int code = Tcl_Eval(interp, script); +int code = Tcl_EvalEx(interp, script, -1, 0); if (code == TCL_ERROR) { Tcl_Obj *options = \fBTcl_GetReturnOptions\fR(interp, code); Tcl_Obj *key = Tcl_NewStringObj("-errorinfo", -1); diff --git a/doc/GetInt.3 b/doc/GetInt.3 index 871f483..5a3304a 100644 --- a/doc/GetInt.3 +++ b/doc/GetInt.3 @@ -51,27 +51,42 @@ in the interpreter's result, and nothing is stored at *\fIintPtr\fR or *\fIdoublePtr\fR or *\fIboolPtr\fR. .PP \fBTcl_GetInt\fR expects \fIsrc\fR to consist of a collection -of integer digits, optionally signed and optionally preceded by -white space. If the first two characters of \fIsrc\fR +of integer digits, optionally signed and optionally preceded and +followed by white space. If the first two characters of \fIsrc\fR after the optional white space and sign are -.QW 0x +.QW \fB0x\fR then \fIsrc\fR is expected to be in hexadecimal form; otherwise, +if the first such characters are +.QW \fB0o\fR +then \fIsrc\fR is expected to be in octal form; otherwise, +if the first such characters are +.QW \fB0b\fR +then \fIsrc\fR is expected to be in binary form; otherwise, if the first such character is -.QW 0 +.QW \fB0\fR then \fIsrc\fR is expected to be in octal form; otherwise, \fIsrc\fR is expected to be in decimal form. .PP \fBTcl_GetDouble\fR expects \fIsrc\fR to consist of a floating-point number, which is: white space; a sign; a sequence of digits; a -decimal point; a sequence of digits; the letter -.QW e ; +decimal point +.QW \fB.\fR ; +a sequence of digits; the letter +.QW \fBe\fR ; a signed decimal exponent; and more white space. Any of the fields may be omitted, except that the digits either before or after the decimal point must be present and if the -.QW e -is present then it must be followed by the exponent number. +.QW \fBe\fR +is present then it must be followed by the exponent number. If there +are no fields apart from the sign and initial sequence of digits +(i.e., no decimal point or exponent indicator), that +initial sequence of digits should take one of the forms that +\fBTcl_GetInt\fR supports, described above. The use of +.QW \fB,\fR +as a decimal point is not supported nor should any other sort of +inter-digit separator be present. .PP \fBTcl_GetBoolean\fR expects \fIsrc\fR to specify a boolean value. If \fIsrc\fR is any of \fB0\fR, \fBfalse\fR, @@ -281,7 +281,7 @@ The \fIhashKeyProc\fR member contains the address of a function called to calculate a hash value for the key. .PP .CS -typedef unsigned int \fBTcl_HashKeyProc\fR( +typedef TCL_HASH_TYPE \fBTcl_HashKeyProc\fR( Tcl_HashTable *\fItablePtr\fR, void *\fIkeyPtr\fR); .CE diff --git a/doc/SetResult.3 b/doc/SetResult.3 index dc8f487..e5b81d7 100644 --- a/doc/SetResult.3 +++ b/doc/SetResult.3 @@ -164,7 +164,7 @@ The source interpreter will have its result reset by this operation. .SH "DEPRECATED INTERFACES" .SS "OLD STRING PROCEDURES" .PP -Use of the following procedures (is deprecated +Use of the following procedures is deprecated since they manipulate the Tcl result as a string. Procedures such as \fBTcl_SetObjResult\fR that manipulate the result as a value @@ -287,12 +287,14 @@ slow destinations like network sockets. .RS .PP The \fBchan copy\fR command transfers data from \fIinputChan\fR until -end of file or \fIsize\fR bytes have been transferred. If no -\fB\-size\fR argument is given, then the copy goes until end of file. -All the data read from \fIinputChan\fR is copied to \fIoutputChan\fR. -Without the \fB\-command\fR option, \fBchan copy\fR blocks until the -copy is complete and returns the number of bytes written to -\fIoutputChan\fR. +end of file or \fIsize\fR bytes or characters have been transferred; +\fIsize\fR is in bytes if the two channels are using the same encoding, +and is in characters otherwise. If no \fB\-size\fR argument is given, +then the copy goes until end of file. All the data read from +\fIinputChan\fR is copied to \fIoutputChan\fR. Without the +\fB\-command\fR option, \fBchan copy\fR blocks until the copy is +complete and returns the number of bytes or characters (using the same +rules as for the \fB\-size\fR option) written to \fIoutputChan\fR. .PP The \fB\-command\fR argument makes \fBchan copy\fR work in the background. In this case it returns immediately and the @@ -547,6 +549,18 @@ this, spawn with "2>@" or ">@" redirection operators onto the write side of a pipe, and then immediately close it in the parent. This is necessary to get an EOF on the read side once the child has exited or otherwise closed its output. +.RS +.PP +Note that the pipe buffering semantics can vary at the operating system level +substantially; it is not safe to assume that a write performed on the output +side of the pipe will appear instantly to the input side. This is a +fundamental difference and Tcl cannot conceal it. The overall stream semantics +\fIare\fR compatible, so blocking reads and writes will not see most of the +differences, but the details of what exactly gets written when are not. This +is most likely to show up when using pipelines for testing; care should be +taken to ensure that deadlocks do not occur and that potential short reads are +allowed for. +.RE .VE 8.6 .TP \fBchan pop \fIchannelId\fR diff --git a/doc/concat.n b/doc/concat.n index 9fe7908..d10f092 100644 --- a/doc/concat.n +++ b/doc/concat.n @@ -20,6 +20,7 @@ This command joins each of its arguments together with spaces after trimming leading and trailing white-space from each of them. If all of the arguments are lists, this has the same effect as concatenating them into a single list. +Arguments that are empty (after trimming) are ignored entirely. It permits any number of arguments; if no \fIarg\fRs are supplied, the result is an empty string. .SH EXAMPLES @@ -271,8 +271,9 @@ limitation as \fBexec\fR wants to communicate over pipes. The Expect extension addresses this issue when communicating with a TUI application. .PP When attempting to execute an application, \fBexec\fR first searches for -the name as it was specified. Then, in order, \fB.com\fR, \fB.exe\fR, and -\fB.bat\fR are appended to the end of the specified name and it searches +the name as it was specified. Then, in order, +\fB.com\fR, \fB.exe\fR, \fB.bat\fR and \fB.cmd\fR +are appended to the end of the specified name and it searches for the longer name. If a directory name was not specified as part of the application name, the following directories are automatically searched in order when attempting to locate the application: @@ -17,14 +17,14 @@ expr \- Evaluate an expression .BE .SH DESCRIPTION .PP -Concatenates \fIarg\fRs (adding separator spaces between them), -evaluates the result as a Tcl expression, and returns the value. -The operators permitted in Tcl expressions include a subset of +Concatenates \fIarg\fRs, separated by a space, into an expression, and evaluates +that expression, returning its value. +The operators permitted in an expression include a subset of the operators permitted in C expressions. For those operators common to both Tcl and C, Tcl applies the same meaning and precedence as the corresponding C operators. -Expressions almost always yield numeric results -(integer or floating-point values). +The value of an expression is often a numeric result, either an integer or a +floating-point value, but may also be a non-numeric value. For example, the expression .PP .CS @@ -32,78 +32,68 @@ For example, the expression .CE .PP evaluates to 14.2. -Tcl expressions differ from C expressions in the way that -operands are specified. Also, Tcl expressions support -non-numeric operands and string comparisons, as well as some +Expressions differ from C expressions in the way that +operands are specified. Expressions also support +non-numeric operands, string comparisons, and some additional operators not found in C. +.PP +When an expression evaluates to an integer, the value is the decimal form of +the integer, and when an expression evaluates to a floating-point number, the +value is the form produced by the \fB%g\fR format specifier of Tcl's +\fBformat\fR command. .SS OPERANDS .PP -A Tcl expression consists of a combination of operands, operators, -parentheses and commas. -White space may be used between the operands and operators and -parentheses (or commas); it is ignored by the expression's instructions. -Where possible, operands are interpreted as integer values. -Integer values may be specified in decimal (the normal case), in binary -(if the first two characters of the operand are \fB0b\fR), in octal -(if the first two characters of the operand are \fB0o\fR), or in hexadecimal -(if the first two characters of the operand are \fB0x\fR). For -compatibility with older Tcl releases, an octal integer value is also -indicated simply when the first character of the operand is \fB0\fR, -whether or not the second character is also \fBo\fR. -If an operand does not have one of the integer formats given -above, then it is treated as a floating-point number if that is -possible. Floating-point numbers may be specified in any of several -common formats making use of the decimal digits, the decimal point \fB.\fR, -the characters \fBe\fR or \fBE\fR indicating scientific notation, and -the sign characters \fB+\fR or \fB\-\fR. For example, all of the -following are valid floating-point numbers: 2.1, 3., 6e4, 7.91e+16. -Also recognized as floating point values are the strings \fBInf\fR -and \fBNaN\fR making use of any case for each character. -If no numeric interpretation is possible (note that all literal -operands that are not numeric or boolean must be quoted with either -braces or with double quotes), then an operand is left as a string -(and only a limited set of operators may be applied to it). -.PP -Operands may be specified in any of the following ways: +An expression consists of a combination of operands, operators, parentheses and +commas, possibly with whitespace between any of these elements, which is +ignored. +An integer operand may be specified in decimal, binary +(the first two characters are \fB0b\fR), octal +(the first two characters are \fB0o\fR), or hexadecimal +(the first two characters are \fB0x\fR) form. For +compatibility with older Tcl releases, an operand that begins with \fB0\fR is +interpreted as an octal integer even if the second character is not \fBo\fR. +A floating-point number may be specified in any of several +common decimal formats, and may use the decimal point \fB.\fR, +\fBe\fR or \fBE\fR for scientific notation, and +the sign characters \fB+\fR and \fB\-\fR. The +following are all valid floating-point numbers: 2.1, 3., 6e4, 7.91e+16. +The strings \fBInf\fR +and \fBNaN\fR, in any combination of case, are also recognized as floating point +values. An operand that doesn't have a numeric interpretation must be quoted +with either braces or with double quotes. +.PP +An operand may be specified in any of the following ways: .IP [1] As a numeric value, either integer or floating-point. .IP [2] As a boolean value, using any form understood by \fBstring is\fR \fBboolean\fR. .IP [3] -As a Tcl variable, using standard \fB$\fR notation. -The variable's value will be used as the operand. +As a variable, using standard \fB$\fR notation. +The value of the variable is then the value of the operand. .IP [4] As a string enclosed in double-quotes. -The expression parser will perform backslash, variable, and -command substitutions on the information between the quotes, -and use the resulting value as the operand +Backslash, variable, and command substitution are performed as described in +\fBTcl\fR. .IP [5] As a string enclosed in braces. -The characters between the open brace and matching close brace -will be used as the operand without any substitutions. +The operand is treated as a braced value as described in \fBTcl\fR. .IP [6] As a Tcl command enclosed in brackets. -The command will be executed and its result will be used as -the operand. +Command substitution is performed as described in \fBTcl\fR. .IP [7] -As a mathematical function whose arguments have any of the above -forms for operands, such as \fBsin($x)\fR. See \fBMATH FUNCTIONS\fR below for +As a mathematical function such as \fBsin($x)\fR, whose arguments have any of the above +forms for operands. See \fBMATH FUNCTIONS\fR below for a discussion of how mathematical functions are handled. .PP -Where the above substitutions occur (e.g. inside quoted strings), they -are performed by the expression's instructions. -However, the command parser may already have performed one round of -substitution before the expression processor was called. -As discussed below, it is usually best to enclose expressions -in braces to prevent the command parser from performing substitutions -on the contents. +Because \fBexpr\fR parses and performs substitutions on values that have +already been parsed and substituted by \fBTcl\fR, it is usually best to enclose +expressions in braces to avoid the first round of substitutions by +\fBTcl\fR. .PP -For some examples of simple expressions, suppose the variable -\fBa\fR has the value 3 and -the variable \fBb\fR has the value 6. -Then the command on the left side of each of the lines below -will produce the value on the right side of the line: +Below are some examples of simple expressions where the value of \fBa\fR is 3 +and the value of \fBb\fR is 6. The command on the left side of each line +produces the value on the right side. .PP .CS .ta 6c @@ -114,34 +104,41 @@ will produce the value on the right side of the line: .CE .SS OPERATORS .PP -The valid operators (most of which are also available as commands in -the \fBtcl::mathop\fR namespace; see the \fBmathop\fR(n) manual page -for details) are listed below, grouped in decreasing order of precedence: +For operators having both a numeric mode and a string mode, the numeric mode is +chosen when all operands have a numeric interpretation. The integer +interpretation of an operand is preferred over the floating-point +interpretation. To ensure string operations on arbitrary values it is generally a +good idea to use \fBeq\fR, \fBne\fR, or the \fBstring\fR command instead of +more versatile operators such as \fB==\fR. +.PP +Unless otherwise specified, operators accept non-numeric operands. The value +of a boolean operation is 1 if true, 0 otherwise. See also \fBstring is\fR +\fBboolean\fR. The valid operators, most of which are also available as +commands in the \fBtcl::mathop\fR namespace (see \fBmathop\fR(n)), are listed +below, grouped in decreasing order of precedence: .TP 20 \fB\-\0\0+\0\0~\0\0!\fR . -Unary minus, unary plus, bit-wise NOT, logical NOT. None of these operators -may be applied to string operands, and bit-wise NOT may be -applied only to integers. +Unary minus, unary plus, bit-wise NOT, logical NOT. These operators +may only be applied to numeric operands, and bit-wise NOT may only be +applied to integers. .TP 20 \fB**\fR . -Exponentiation. Valid for any numeric operands. +Exponentiation. Valid for numeric operands. .TP 20 \fB*\0\0/\0\0%\fR . -Multiply, divide, remainder. None of these operators may be -applied to string operands, and remainder may be applied only -to integers. -The remainder will always have the same sign as the divisor and -an absolute value smaller than the absolute value of the divisor. +Multiply and divide, which are valid for numeric operands, and remainder, which +is valid for integers. The remainder, an absolute value smaller than the +absolute value of the divisor, has the same sign as the divisor. .RS .PP -When applied to integers, the division and remainder operators can be -considered to partition the number line into a sequence of equal-sized -adjacent non-overlapping pieces where each piece is the size of the divisor; -the division result identifies which piece the divisor lay within, and the -remainder result identifies where within that piece the divisor lay. A +When applied to integers, division and remainder can be +considered to partition the number line into a sequence of +adjacent non-overlapping pieces, where each piece is the size of the divisor; +the quotient identifies which piece the dividend lies within, and the +remainder identifies where within that piece the dividend lies. A consequence of this is that the result of .QW "-57 \fB/\fR 10" is always -6, and the result of @@ -151,177 +148,157 @@ is always 3. .TP 20 \fB+\0\0\-\fR . -Add and subtract. Valid for any numeric operands. +Add and subtract. Valid for numeric operands. .TP 20 \fB<<\0\0>>\fR . -Left and right shift. Valid for integer operands only. +Left and right shift. Valid for integers. A right shift always propagates the sign bit. .TP 20 \fB<\0\0>\0\0<=\0\0>=\fR . -Boolean less, greater, less than or equal, and greater than or equal. -Each operator produces 1 if the condition is true, 0 otherwise. -These operators may be applied to strings as well as numeric operands, -in which case string comparison is used. +Boolean less than, greater than, less than or equal, and greater than or equal. .TP 20 \fB==\0\0!=\fR . -Boolean equal and not equal. Each operator produces a zero/one result. -Valid for all operand types. +Boolean equal and not equal. .TP 20 \fBeq\0\0ne\fR . -Boolean string equal and string not equal. Each operator produces a -zero/one result. The operand types are interpreted only as strings. +Boolean string equal and string not equal. .TP 20 \fBin\0\0ni\fR . -List containment and negated list containment. Each operator produces -a zero/one result and treats its first argument as a string and its -second argument as a Tcl list. The \fBin\fR operator indicates -whether the first argument is a member of the second argument list; -the \fBni\fR operator inverts the sense of the result. +List containment and negated list containment. The first argument is +interpreted as a string, the second as a list. \fBin\fR tests for membership +in the list, and \fBni\fR is the inverse. .TP 20 \fB&\fR . -Bit-wise AND. Valid for integer operands only. +Bit-wise AND. Valid for integer operands. .TP 20 \fB^\fR . -Bit-wise exclusive OR. Valid for integer operands only. +Bit-wise exclusive OR. Valid for integer operands. .TP 20 \fB|\fR . -Bit-wise OR. Valid for integer operands only. +Bit-wise OR. Valid for integer operands. .TP 20 \fB&&\fR . -Logical AND. Produces a 1 result if both operands are non-zero, -0 otherwise. -Valid for boolean and numeric (integers or floating-point) operands only. +Logical AND. If both operands are true, the result is 1, or 0 otherwise. + .TP 20 \fB||\fR . -Logical OR. Produces a 0 result if both operands are zero, 1 otherwise. -Valid for boolean and numeric (integers or floating-point) operands only. +Logical OR. If both operands are false, the result is 0, or 1 otherwise. .TP 20 \fIx\fB?\fIy\fB:\fIz\fR . -If-then-else, as in C. If \fIx\fR -evaluates to non-zero, then the result is the value of \fIy\fR. -Otherwise the result is the value of \fIz\fR. -The \fIx\fR operand must have a boolean or numeric value. -.PP -See the C manual for more details on the results -produced by each operator. -The exponentiation operator promotes types like the multiply and -divide operators, and produces a result that is the same as the output -of the \fBpow\fR function (after any type conversions.) -All of the binary operators but exponentiation group left-to-right -within the same precedence level; exponentiation groups right-to-left. For example, the command +If-then-else, as in C. If \fIx\fR is false , the result is the value of +\fIy\fR. Otherwise the result is the value of \fIz\fR. +.PP +The exponentiation operator promotes types in the same way that the multiply +and divide operators do, and the result is is the same as the result of +\fBpow\fR. +Exponentiation groups right-to-left within a precedence level. Other binary +operators group left-to-right. For example, the value of .PP .CS \fBexpr\fR {4*2 < 7} .CE .PP -returns 0, while +is 0, while the value of .PP .CS \fBexpr\fR {2**3**2} .CE .PP -returns 512. +is 512. .PP -The \fB&&\fR, \fB||\fR, and \fB?:\fR operators have +As in C, \fB&&\fR, \fB||\fR, and \fB?:\fR feature .QW "lazy evaluation" , -just as in C, which means that operands are not evaluated if they are -not needed to determine the outcome. For example, in the command +which means that operands are not evaluated if they are +not needed to determine the outcome. For example, in .PP .CS \fBexpr\fR {$v ? [a] : [b]} .CE .PP -only one of -.QW \fB[a]\fR -or -.QW \fB[b]\fR -will actually be evaluated, -depending on the value of \fB$v\fR. Note, however, that this is -only true if the entire expression is enclosed in braces; otherwise -the Tcl parser will evaluate both -.QW \fB[a]\fR -and -.QW \fB[b]\fR -before invoking the \fBexpr\fR command. +only one of \fB[a]\fR or \fB[b]\fR is evaluated, +depending on the value of \fB$v\fR. This is not true of the normal Tcl parser, +so it is normally recommended to enclose the arguments to \fBexpr\fR in braces. +Without braces, as in +\fBexpr\fR $v ? [a] : [b] +both \fB[a]\fR and \fB[b]\fR are evaluated before \fBexpr\fR is even called. +.PP +For more details on the results +produced by each operator, see the documentation for C. .SS "MATH FUNCTIONS" .PP -When the expression parser encounters a mathematical function -such as \fBsin($x)\fR, it replaces it with a call to an ordinary -Tcl function in the \fBtcl::mathfunc\fR namespace. The processing -of an expression such as: +A mathematical function such as \fBsin($x)\fR is replaced with a call to an ordinary +Tcl command in the \fBtcl::mathfunc\fR namespace. The evaluation +of an expression such as .PP .CS \fBexpr\fR {sin($x+$y)} .CE .PP -is the same in every way as the processing of: +is the same in every way as the evaluation of .PP .CS \fBexpr\fR {[tcl::mathfunc::sin [\fBexpr\fR {$x+$y}]]} .CE .PP -which in turn is the same as the processing of: +which in turn is the same as the evaluation of .PP .CS tcl::mathfunc::sin [\fBexpr\fR {$x+$y}] .CE .PP -The executor will search for \fBtcl::mathfunc::sin\fR using the usual -rules for resolving functions in namespaces. Either -\fB::tcl::mathfunc::sin\fR or \fB[namespace -current]::tcl::mathfunc::sin\fR will satisfy the request, and others -may as well (depending on the current \fBnamespace path\fR setting). +\fBtcl::mathfunc::sin\fR is resolved as described in +\fBNAMESPACE RESOLUTION\fR in the \fBnamespace\fR(n) documentation. Given the +default value of \fBnamespace path\fR, \fB[namespace +current]::tcl::mathfunc::sin\fR or \fB::tcl::mathfunc::sin\fR are the typical +resolutions. .PP -Some mathematical functions have several arguments, separated by commas like in C. Thus: +As in C, a mathematical function may accept multiple arguments separated by commas. Thus, .PP .CS \fBexpr\fR {hypot($x,$y)} .CE .PP -ends up as +becomes .PP .CS tcl::mathfunc::hypot $x $y .CE .PP -See the \fBmathfunc\fR(n) manual page for the math functions that are +See the \fBmathfunc\fR(n) documentation for the math functions that are available by default. .SS "TYPES, OVERFLOW, AND PRECISION" .PP -All internal computations involving integers are done calling on the -LibTomMath multiple precision integer library as required so that all -integer calculations are performed exactly. Note that in Tcl releases -prior to 8.5, integer calculations were performed with one of the C types +When needed to guarantee exact performance, internal computations involving +integers use the LibTomMath multiple precision integer library. In Tcl releases +prior to 8.5, integer calculations were performed using one of the C types \fIlong int\fR or \fITcl_WideInt\fR, causing implicit range truncation in those calculations where values overflowed the range of those types. -Any code that relied on these implicit truncations will need to explicitly -add \fBint()\fR or \fBwide()\fR function calls to expressions at the points -where such truncation is required to take place. +Any code that relied on these implicit truncations should instead call +\fBint()\fR or \fBwide()\fR, which do truncate. .PP -All internal computations involving floating-point are -done with the C type \fIdouble\fR. -When converting a string to floating-point, exponent overflow is +Internal floating-point computations are +performed using the \fIdouble\fR C type. +When converting a string to floating-point value, exponent overflow is detected and results in the \fIdouble\fR value of \fBInf\fR or \fB\-Inf\fR as appropriate. Floating-point overflow and underflow are detected to the degree supported by the hardware, which is generally -pretty reliable. +fairly reliable. .PP -Conversion among internal representations for integer, floating-point, -and string operands is done automatically as needed. -For arithmetic computations, integers are used until some -floating-point number is introduced, after which floating-point is used. -For example, +Conversion among internal representations for integer, floating-point, and +string operands is done automatically as needed. For arithmetic computations, +integers are used until some floating-point number is introduced, after which +floating-point values are used. For example, .PP .CS \fBexpr\fR {5 / 4} @@ -335,82 +312,62 @@ returns 1, while .CE .PP both return 1.25. -Floating-point values are always returned with a +A floating-point result can be distinguished from an integer result by the +presence of either .QW \fB.\fR -or an +or .QW \fBe\fR -so that they will not look like integer values. For example, +.PP +. For example, .PP .CS \fBexpr\fR {20.0/5.0} .CE .PP returns \fB4.0\fR, not \fB4\fR. -.SS "STRING OPERATIONS" -.PP -String values may be used as operands of the comparison operators, -although the expression evaluator tries to do comparisons as integer -or floating-point when it can, -i.e., when all arguments to the operator allow numeric interpretations, -except in the case of the \fBeq\fR and \fBne\fR operators. -If one of the operands of a comparison is a string and the other -has a numeric value, a canonical string representation of the numeric -operand value is generated to compare with the string operand. -Canonical string representation for integer values is a decimal string -format. Canonical string representation for floating-point values -is that produced by the \fB%g\fR format specifier of Tcl's -\fBformat\fR command. For example, the commands -.PP -.CS -\fBexpr\fR {"0x03" > "2"} -\fBexpr\fR {"0y" > "0x12"} -.CE -.PP -both return 1. The first comparison is done using integer -comparison, and the second is done using string comparison. -Because of Tcl's tendency to treat values as numbers whenever -possible, it is not generally a good idea to use operators like \fB==\fR -when you really want string comparison and the values of the -operands could be arbitrary; it is better in these cases to use -the \fBeq\fR or \fBne\fR operators, or the \fBstring\fR command instead. .SH "PERFORMANCE CONSIDERATIONS" .PP -Enclose expressions in braces for the best speed and the smallest -storage requirements. -This allows the Tcl bytecode compiler to generate the best code. -.PP -As mentioned above, expressions are substituted twice: -once by the Tcl parser and once by the \fBexpr\fR command. -For example, the commands +Where an expression contains syntax that Tcl would otherwise perform +substitutions on, enclosing an expression in braces or otherwise quoting it +so that it's a static value allows the Tcl compiler to generate bytecode for +the expression, resulting in better speed and smaller storage requirements. +This also avoids issues that can arise if Tcl is allowed to perform +substitution on the value before \fBexpr\fR is called. .PP +In the following example, the value of the expression is 11 because the Tcl parser first +substitutes \fB$b\fR and \fBexpr\fR then substitutes \fB$a\fR. Enclosing the +expression in braces would result in a syntax error. .CS set a 3 set b {$a + 2} \fBexpr\fR $b*4 .CE .PP -return 11, not a multiple of 4. -This is because the Tcl parser will first substitute \fB$a + 2\fR for -the variable \fBb\fR, -then the \fBexpr\fR command will evaluate the expression \fB$a + 2*4\fR. -.PP -Most expressions do not require a second round of substitutions. -Either they are enclosed in braces or, if not, -their variable and command substitutions yield numbers or strings -that do not themselves require substitutions. -However, because a few unbraced expressions -need two rounds of substitutions, -the bytecode compiler must emit -additional instructions to handle this situation. -The most expensive code is required for -unbraced expressions that contain command substitutions. -These expressions must be implemented by generating new code -each time the expression is executed. -When the expression is unbraced to allow the substitution of a function or -operator, consider using the commands documented in the \fBmathfunc\fR(n) or -\fBmathop\fR(n) manual pages directly instead. + +When an expression is generated at runtime, like the one above is, the bytcode +compiler must ensure that new code is generated each time the expression +is evaluated. This is the most costly kind of expression from a performance +perspective. In such cases, consider directly using the commands described in +the \fBmathfunc\fR(n) or \fBmathop\fR(n) documentation instead of \fBexpr\fR. + +Most expressions are not formed at runtime, but are literal strings or contain +substitutions that don't introduce other substitutions. To allow the bytecode +compiler to work with an expression as a string literal at compilation time, +ensure that it contains no substitutions or that it is enclosed in braces or +otherwise quoted to prevent Tcl from performing substitutions, allowing +\fBexpr\fR to perform them instead. .SH EXAMPLES .PP +A numeric comparison whose result is 1: +.CS +\fBexpr\fR {"0x03" > "2"} +.CE +.PP +A string comparison whose result is 1: +.CS +\fBexpr\fR {"0y" > "0x12"} +.CE +.PP Define a procedure that computes an .QW interesting mathematical function: @@ -444,8 +401,8 @@ each other: puts "a and b are [\fBexpr\fR {$a eq $b ? {equal} : {different}}]" .CE .PP -Set a variable to whether an environment variable is both defined at -all and also set to a true boolean value: +Set a variable indicating whether an environment variable is defined and has +value of true: .PP .CS set isTrue [\fBexpr\fR { diff --git a/doc/fcopy.n b/doc/fcopy.n index e5dd1d6..d39c803 100644 --- a/doc/fcopy.n +++ b/doc/fcopy.n @@ -25,12 +25,15 @@ network sockets. .PP The \fBfcopy\fR command transfers data from \fIinchan\fR until end of file -or \fIsize\fR bytes have been -transferred. If no \fB\-size\fR argument is given, +or \fIsize\fR bytes or characters have been +transferred; \fIsize\fR is in bytes if the two channels are using the +same encoding, and is in characters otherwise. +If no \fB\-size\fR argument is given, then the copy goes until end of file. All the data read from \fIinchan\fR is copied to \fIoutchan\fR. Without the \fB\-command\fR option, \fBfcopy\fR blocks until the copy is complete -and returns the number of bytes written to \fIoutchan\fR. +and returns the number of bytes or characters (using the same rules as +for the \fB\-size\fR option) written to \fIoutchan\fR. .PP The \fB\-command\fR argument makes \fBfcopy\fR work in the background. In this case it returns immediately and the \fIcallback\fR is invoked @@ -174,3 +177,6 @@ vwait done eof(n), fblocked(n), fconfigure(n), file(n) .SH KEYWORDS blocking, channel, end of line, end of file, nonblocking, read, translation +'\" Local Variables: +'\" mode: nroff +'\" End: @@ -162,7 +162,9 @@ returns \fB/home\fR (or something similar). \fBfile executable \fIname\fR . Returns \fB1\fR if file \fIname\fR is executable by the current user, -\fB0\fR otherwise. +\fB0\fR otherwise. On Windows, which does not have an executable attribute, +the command treats all directories and any files with extensions +\fBexe\fR, \fBcom\fR, \fBcmd\fR or \fBbat\fR as executable. .TP \fBfile exists \fIname\fR . @@ -482,10 +484,9 @@ not the effective ones. .TP \fBWindows\fR\0\0\0\0 . -The \fBfile owned\fR subcommand currently always reports that the current user -is the owner of the file, without regard for what the operating system -believes to be true, making an ownership test useless. This issue (#3613671) -may be fixed in a future release of Tcl. +The \fBfile owned\fR subcommand uses the user identifier (SID) of +the process token, not the thread token which may be impersonating +some other user. .SH EXAMPLES .PP This procedure shows how to search for C files in a given directory @@ -418,7 +418,10 @@ set token [::http::geturl https://my.secure.site/] \fB::http::unregister\fR \fIproto\fR . This procedure unregisters a protocol handler that was previously -registered via \fB::http::register\fR. +registered via \fB::http::register\fR, returning a two-item list of +the default port and handler command that was previously installed +(via \fB::http::register\fR) if there was such a handler, and an error if +there was no such handler. .SH ERRORS The \fB::http::geturl\fR procedure will raise errors in the following cases: invalid command line options, @@ -34,8 +34,9 @@ one or two fields. If there is only a single field in the specifier then it is the name of the argument; if there are two fields, then the first is the argument name and the second is its default value. Arguments with default values that are followed by non-defaulted -arguments become required arguments. In 8.6 this will be considered an -error. +arguments become required arguments; enough actual arguments must be +supplied to allow all arguments up to and including the last required +formal argument. .PP When \fIname\fR is invoked a local variable will be created for each of the formal arguments to the procedure; its @@ -48,11 +49,14 @@ actual arguments for all the formal arguments that do not have defaults, and there must not be any extra actual arguments. Arguments with default values that are followed by non-defaulted -arguments become required arguments (in 8.6 it will be considered an -error). +arguments become de-facto required arguments, though this may change +in a future version of Tcl; portable code should ensure that all +optional arguments come after all required arguments. +.PP There is one special case to permit procedures with variable numbers of arguments. If the last formal argument has the name -\fBargs\fR, then a call to the procedure may contain more actual arguments +.QW \fBargs\fR , +then a call to the procedure may contain more actual arguments than the procedure has formal arguments. In this case, all of the actual arguments starting at the one that would be assigned to \fBargs\fR are combined into a list (as if the \fBlist\fR command had been used); this combined value @@ -80,6 +84,20 @@ If an error occurs while executing the procedure body, then the procedure-as-a-whole will return that same error. .SH EXAMPLES .PP +This is a procedure that takes two arguments and prints both their sum +and their product. It also returns the string +.QW OK +to the caller as an explicit result. +.PP +.CS +\fBproc\fR printSumProduct {x y} { + set sum [expr {$x + $y}] + set prod [expr {$x * $y}] + puts "sum is $sum, product is $prod" + return "OK" +} +.CE +.PP This is a procedure that accepts arbitrarily many arguments and prints them out, one by one. .PP @@ -123,9 +123,7 @@ with conversion character \fBu\fR. .TP \fBi\fR . -The input substring must be an integer. The base (i.e. decimal, binary, -octal, or hexadecimal) is determined in the same fashion as described in -\fBexpr\fR. The integer value is stored in the variable, +The input substring must be an integer. The base (i.e. decimal, octal, or hexadecimal) is determined by the C convention (leading 0 for octal; prefix 0x for hexadecimal). The integer value is stored in the variable, truncated as required by the size modifier value. .TP \fBc\fR diff --git a/doc/variable.n b/doc/variable.n index a6e545f..8228859 100644 --- a/doc/variable.n +++ b/doc/variable.n @@ -45,7 +45,8 @@ linked to the corresponding namespace variables (and therefore these variables are listed by \fBinfo vars\fR.) In this way the \fBvariable\fR command resembles the \fBglobal\fR command, although the \fBglobal\fR command -only links to variables in the global namespace. +resolves variable names with respect to the global namespace instead +of the current namespace of the procedure. If any \fIvalue\fRs are given, they are used to modify the values of the associated namespace variables. If a namespace variable does not exist, @@ -98,3 +99,7 @@ namespace eval foo { global(n), namespace(n), upvar(n) .SH KEYWORDS global, namespace, procedure, variable +.\" Local variables: +.\" mode: nroff +.\" fill-column: 78 +.\" End: @@ -174,7 +174,11 @@ to the \fBzlib push\fR command: .VS "TIP 400" Sets the compression dictionary to use when working with compressing or decompressing the data to be \fIbinData\fR. Not valid for transformations that -work with gzip-format data. +work with gzip-format data. The dictionary should consist of strings (byte +sequences) that are likely to be encountered later in the data to be compressed, +with the most commonly used strings preferably put towards the end of the +dictionary. Tcl provides no mechanism for choosing a good such dictionary for +a particular data sequence. .VE .TP \fB\-header\fI dictionary\fR @@ -207,11 +211,13 @@ compression algorithm depends on what format is being produced or consumed. .TP \fB\-dictionary\fI binData\fR .VS "TIP 400" -This read-write options gets or sets the compression dictionary to use when -working with compressing or decompressing the data to be \fIbinData\fR. It is -not valid for transformations that work with gzip-format data, and should not -normally be set on compressing transformations other than at the point where -the transformation is stacked. +This read-write options gets or sets the initial compression dictionary to use +when working with compressing or decompressing the data to be \fIbinData\fR. +It is not valid for transformations that work with gzip-format data, and should +not normally be set on compressing transformations other than at the point where +the transformation is stacked. Note that this cannot be used to get the +current active compression dictionary mid-stream, as that information is not +exposed by the underlying library. .VE .TP \fB\-flush\fI type\fR |