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diff --git a/usr/man/mann/expr.n b/usr/man/mann/expr.n new file mode 100755 index 000000000..ce8f066b2 --- /dev/null +++ b/usr/man/mann/expr.n @@ -0,0 +1,689 @@ +'\" +'\" Copyright (c) 1993 The Regents of the University of California. +'\" Copyright (c) 1994-2000 Sun Microsystems, Inc. +'\" Copyright (c) 2005 by Kevin B. Kenny <kennykb@acm.org>. All rights reserved +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +.\" The -*- nroff -*- definitions below are for supplemental macros used +.\" in Tcl/Tk manual entries. +.\" +.\" .AP type name in/out ?indent? +.\" Start paragraph describing an argument to a library procedure. +.\" type is type of argument (int, etc.), in/out is either "in", "out", +.\" or "in/out" to describe whether procedure reads or modifies arg, +.\" and indent is equivalent to second arg of .IP (shouldn't ever be +.\" needed; use .AS below instead) +.\" +.\" .AS ?type? ?name? +.\" Give maximum sizes of arguments for setting tab stops. Type and +.\" name are examples of largest possible arguments that will be passed +.\" to .AP later. If args are omitted, default tab stops are used. +.\" +.\" .BS +.\" Start box enclosure. From here until next .BE, everything will be +.\" enclosed in one large box. +.\" +.\" .BE +.\" End of box enclosure. +.\" +.\" .CS +.\" Begin code excerpt. +.\" +.\" .CE +.\" End code excerpt. +.\" +.\" .VS ?version? ?br? +.\" Begin vertical sidebar, for use in marking newly-changed parts +.\" of man pages. The first argument is ignored and used for recording +.\" the version when the .VS was added, so that the sidebars can be +.\" found and removed when they reach a certain age. If another argument +.\" is present, then a line break is forced before starting the sidebar. +.\" +.\" .VE +.\" End of vertical sidebar. +.\" +.\" .DS +.\" Begin an indented unfilled display. +.\" +.\" .DE +.\" End of indented unfilled display. +.\" +.\" .SO ?manpage? +.\" Start of list of standard options for a Tk widget. The manpage +.\" argument defines where to look up the standard options; if +.\" omitted, defaults to "options". The options follow on successive +.\" lines, in three columns separated by tabs. +.\" +.\" .SE +.\" End of list of standard options for a Tk widget. +.\" +.\" .OP cmdName dbName dbClass +.\" Start of description of a specific option. cmdName gives the +.\" option's name as specified in the class command, dbName gives +.\" the option's name in the option database, and dbClass gives +.\" the option's class in the option database. +.\" +.\" .UL arg1 arg2 +.\" Print arg1 underlined, then print arg2 normally. +.\" +.\" .QW arg1 ?arg2? +.\" Print arg1 in quotes, then arg2 normally (for trailing punctuation). +.\" +.\" .PQ arg1 ?arg2? +.\" Print an open parenthesis, arg1 in quotes, then arg2 normally +.\" (for trailing punctuation) and then a closing parenthesis. +.\" +.\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. +.if t .wh -1.3i ^B +.nr ^l \n(.l +.ad b +.\" # Start an argument description +.de AP +.ie !"\\$4"" .TP \\$4 +.el \{\ +. ie !"\\$2"" .TP \\n()Cu +. el .TP 15 +.\} +.ta \\n()Au \\n()Bu +.ie !"\\$3"" \{\ +\&\\$1 \\fI\\$2\\fP (\\$3) +.\".b +.\} +.el \{\ +.br +.ie !"\\$2"" \{\ +\&\\$1 \\fI\\$2\\fP +.\} +.el \{\ +\&\\fI\\$1\\fP +.\} +.\} +.. +.\" # define tabbing values for .AP +.de AS +.nr )A 10n +.if !"\\$1"" .nr )A \\w'\\$1'u+3n +.nr )B \\n()Au+15n +.\" +.if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n +.nr )C \\n()Bu+\\w'(in/out)'u+2n +.. +.AS Tcl_Interp Tcl_CreateInterp in/out +.\" # BS - start boxed text +.\" # ^y = starting y location +.\" # ^b = 1 +.de BS +.br +.mk ^y +.nr ^b 1u +.if n .nf +.if n .ti 0 +.if n \l'\\n(.lu\(ul' +.if n .fi +.. +.\" # BE - end boxed text (draw box now) +.de BE +.nf +.ti 0 +.mk ^t +.ie n \l'\\n(^lu\(ul' +.el \{\ +.\" Draw four-sided box normally, but don't draw top of +.\" box if the box started on an earlier page. +.ie !\\n(^b-1 \{\ +\h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' +.\} +.el \}\ +\h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' +.\} +.\} +.fi +.br +.nr ^b 0 +.. +.\" # VS - start vertical sidebar +.\" # ^Y = starting y location +.\" # ^v = 1 (for troff; for nroff this doesn't matter) +.de VS +.if !"\\$2"" .br +.mk ^Y +.ie n 'mc \s12\(br\s0 +.el .nr ^v 1u +.. +.\" # VE - end of vertical sidebar +.de VE +.ie n 'mc +.el \{\ +.ev 2 +.nf +.ti 0 +.mk ^t +\h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' +.sp -1 +.fi +.ev +.\} +.nr ^v 0 +.. +.\" # Special macro to handle page bottom: finish off current +.\" # box/sidebar if in box/sidebar mode, then invoked standard +.\" # page bottom macro. +.de ^B +.ev 2 +'ti 0 +'nf +.mk ^t +.if \\n(^b \{\ +.\" Draw three-sided box if this is the box's first page, +.\" draw two sides but no top otherwise. +.ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c +.el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c +.\} +.if \\n(^v \{\ +.nr ^x \\n(^tu+1v-\\n(^Yu +\kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c +.\} +.bp +'fi +.ev +.if \\n(^b \{\ +.mk ^y +.nr ^b 2 +.\} +.if \\n(^v \{\ +.mk ^Y +.\} +.. +.\" # DS - begin display +.de DS +.RS +.nf +.sp +.. +.\" # DE - end display +.de DE +.fi +.RE +.sp +.. +.\" # SO - start of list of standard options +.de SO +'ie '\\$1'' .ds So \\fBoptions\\fR +'el .ds So \\fB\\$1\\fR +.SH "STANDARD OPTIONS" +.LP +.nf +.ta 5.5c 11c +.ft B +.. +.\" # SE - end of list of standard options +.de SE +.fi +.ft R +.LP +See the \\*(So manual entry for details on the standard options. +.. +.\" # OP - start of full description for a single option +.de OP +.LP +.nf +.ta 4c +Command-Line Name: \\fB\\$1\\fR +Database Name: \\fB\\$2\\fR +Database Class: \\fB\\$3\\fR +.fi +.IP +.. +.\" # CS - begin code excerpt +.de CS +.RS +.nf +.ta .25i .5i .75i 1i +.. +.\" # CE - end code excerpt +.de CE +.fi +.RE +.. +.\" # UL - underline word +.de UL +\\$1\l'|0\(ul'\\$2 +.. +.\" # QW - apply quotation marks to word +.de QW +.ie '\\*(lq'"' ``\\$1''\\$2 +.\"" fix emacs highlighting +.el \\*(lq\\$1\\*(rq\\$2 +.. +.\" # PQ - apply parens and quotation marks to word +.de PQ +.ie '\\*(lq'"' (``\\$1''\\$2)\\$3 +.\"" fix emacs highlighting +.el (\\*(lq\\$1\\*(rq\\$2)\\$3 +.. +.\" # QR - quoted range +.de QR +.ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3 +.\"" fix emacs highlighting +.el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3 +.. +.\" # MT - "empty" string +.de MT +.QW "" +.. +.TH expr n 8.5 Tcl "Tcl Built-In Commands" +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +expr \- Evaluate an expression +.SH SYNOPSIS +\fBexpr \fIarg \fR?\fIarg arg ...\fR? +.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 +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). +For example, the expression +.CS +\fBexpr 8.2 + 6\fR +.CE +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 +additional operators not found in C. +.SS OPERANDS +.PP +A Tcl expression consists of a combination of operands, operators, +and parentheses. +White space may be used between the operands and operators and +parentheses; it is ignored by the expression's instructions. +Where possible, operands are interpreted as integer values. +.VS 8.5 +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. +.VE 8.5 +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: +.IP [1] +As a numeric value, either integer or floating-point. +.IP [2] +As a boolean value, using any form understood by \fBstring is boolean\fR. +.IP [3] +As a Tcl variable, using standard \fB$\fR notation. +The variable's value will be used as the operand. +.IP [4] +As a string enclosed in double-quotes. +The expression parser will perform backslash, variable, and +command substitutions on the information between the quotes, +and use the resulting value as the operand +.IP [5] +As a string enclosed in braces. +The characters between the open brace and matching close brace +will be used as the operand without any substitutions. +.IP [6] +As a Tcl command enclosed in brackets. +The command will be executed and its result will be used as +the operand. +.IP [7] +As a mathematical function whose arguments have any of the above +forms for operands, such as \fBsin($x)\fR. See \fBMATH FUNCTIONS\fR below for +a discussion of how mathematical functions are handled. +.LP +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. +.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: +.CS +.ta 6c +\fBexpr\fR 3.1 + $a \fI6.1\fR +\fBexpr\fR 2 + "$a.$b" \fI5.6\fR +\fBexpr\fR 4*[llength "6 2"] \fI8\fR +\fBexpr\fR {{word one} < "word $a"} \fI0\fR +.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: +.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. +.TP 20 +\fB**\fR +.VS 8.5 +Exponentiation. Valid for any numeric operands. +.VE 8.5 +.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. +.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 +consequence of this is that the result of +.QW "-57 \fB/\fR 10" +is always -6, and the result of +.QW "-57 \fB%\fR 10" +is always 3. +.RE +.TP 20 +\fB+\0\0\-\fR +Add and subtract. Valid for any numeric operands. +.TP 20 +\fB<<\0\0>>\fR +Left and right shift. Valid for integer operands only. +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. +.TP 20 +\fB==\0\0!=\fR +Boolean equal and not equal. Each operator produces a zero/one result. +Valid for all operand types. +.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. +.TP 20 +\fBin\0\0ni\fR +.VS 8.5 +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. +.VE 8.5 +.TP 20 +\fB&\fR +Bit-wise AND. Valid for integer operands only. +.TP 20 +\fB^\fR +Bit-wise exclusive OR. Valid for integer operands only. +.TP 20 +\fB|\fR +Bit-wise OR. Valid for integer operands only. +.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. +.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. +.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. +.LP +See the C manual for more details on the results +produced by each operator. +.VS 8.5 +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.) +.VE 8.5 +All of the binary operators group left-to-right within the same +precedence level. For example, the command +.CS +\fBexpr\fR {4*2 < 7} +.CE +returns 0. +.PP +The \fB&&\fR, \fB||\fR, and \fB?:\fR operators have +.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 +.CS +\fBexpr {$v ? [a] : [b]}\fR +.CE +only one of +.QW \fB[a]\fR +or +.QW \fB[b]\fR +will actually be evaluated, +depending on the value of \fB$v\fR. Note, however, that this is +only true if the entire expression is enclosed in braces; otherwise +the Tcl parser will evaluate both +.QW \fB[a]\fR +and +.QW \fB[b]\fR +before invoking the \fBexpr\fR command. +.SS "MATH FUNCTIONS" +.PP +.VS 8.5 +When the expression parser encounters a mathematical function +such as \fBsin($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: +.CS +\fBexpr {sin($x+$y)}\fR +.CE +is the same in every way as the processing of: +.CS +\fBexpr {[tcl::mathfunc::sin [expr {$x+$y}]]}\fR +.CE +which in turn is the same as the processing of: +.CS +\fBtcl::mathfunc::sin [expr {$x+$y}]\fR +.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). +.PP +See the \fBmathfunc\fR(n) manual page for the math functions that are +available by default. +.VE 8.5 +.SS "TYPES, OVERFLOW, AND PRECISION" +.PP +.VS 8.5 +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 +\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. +.VE 8.5 +.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 +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. +.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, +.CS +\fBexpr\fR {5 / 4} +.CE +returns 1, while +.CS +\fBexpr\fR {5 / 4.0} +\fBexpr\fR {5 / ( [string length "abcd"] + 0.0 )} +.CE +both return 1.25. +Floating-point values are always returned with a +.QW \fB.\fR +or an +.QW \fBe\fR +so that they will not look like integer values. For example, +.CS +\fBexpr\fR {20.0/5.0} +.CE +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 +.CS +\fBexpr {"0x03" > "2"}\fR +\fBexpr {"0y" > "0x12"}\fR +.CE +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 +.CS +\fBset a 3\fR +\fBset b {$a + 2}\fR +\fBexpr $b*4\fR +.CE +return 11, not a multiple of 4. +This is because the Tcl parser will first substitute \fB$a + 2\fR for +the variable \fBb\fR, +then the \fBexpr\fR command will evaluate the expression \fB$a + 2*4\fR. +.PP +Most expressions do not require a second round of substitutions. +Either they are enclosed in braces or, if not, +their variable and command substitutions yield numbers or strings +that do not themselves require substitutions. +However, because a few unbraced expressions +need two rounds of substitutions, +the bytecode compiler must emit +additional instructions to handle this situation. +The most expensive code is required for +unbraced expressions that contain command substitutions. +These expressions must be implemented by generating new code +each time the expression is executed. +.VS 8.5 +When the expression is unbraced to allow the substitution of a function or +operator, consider using the commands documented in the \fBmathfunc\fR(n) or +\fBmathop\fR(n) manual pages directly instead. +.VE 8.5 +.SH EXAMPLES +Define a procedure that computes an +.QW interesting +mathematical function: +.CS +proc tcl::mathfunc::calc {x y} { + \fBexpr\fR { ($x**2 - $y**2) / exp($x**2 + $y**2) } +} +.CE +.PP +Convert polar coordinates into cartesian coordinates: +.CS +# convert from ($radius,$angle) +set x [\fBexpr\fR { $radius * cos($angle) }] +set y [\fBexpr\fR { $radius * sin($angle) }] +.CE +.PP +Convert cartesian coordinates into polar coordinates: +.CS +# convert from ($x,$y) +set radius [\fBexpr\fR { hypot($y, $x) }] +set angle [\fBexpr\fR { atan2($y, $x) }] +.CE +.PP +Print a message describing the relationship of two string values to +each other: +.CS +puts "a and b are [\fBexpr\fR {$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: +.CS +set isTrue [\fBexpr\fR { + [info exists ::env(SOME_ENV_VAR)] && + [string is true -strict $::env(SOME_ENV_VAR)] +}] +.CE +.PP +Generate a random integer in the range 0..99 inclusive: +.CS +set randNum [\fBexpr\fR { int(100 * rand()) }] +.CE +.SH "SEE ALSO" +array(n), for(n), if(n), mathfunc(n), mathop(n), namespace(n), proc(n), +string(n), Tcl(n), while(n) +.SH KEYWORDS +arithmetic, boolean, compare, expression, fuzzy comparison +.SH COPYRIGHT +.nf +Copyright (c) 1993 The Regents of the University of California. +Copyright (c) 1994-2000 Sun Microsystems Incorporated. +Copyright (c) 2005 by Kevin B. Kenny <kennykb@acm.org>. All rights reserved. +.fi |