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Diffstat (limited to 'doc/interp.n')
| -rw-r--r-- | doc/interp.n | 162 |
1 files changed, 103 insertions, 59 deletions
diff --git a/doc/interp.n b/doc/interp.n index c753ee9..2cc082b 100644 --- a/doc/interp.n +++ b/doc/interp.n @@ -1,12 +1,13 @@ '\" '\" Copyright (c) 1995-1996 Sun Microsystems, Inc. '\" Copyright (c) 2004 Donal K. Fellows +'\" Copyright (c) 2006-2008 Joe Mistachkin. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" .so man.macros -.TH interp n 7.6 Tcl "Tcl Built-In Commands" +.TH interp n 8.6 Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME @@ -33,10 +34,7 @@ command to be invoked in its master interpreter or in another slave interpreter. The only other connections between interpreters are through environment variables (the \fBenv\fR variable), which are normally shared among all interpreters in the application, -.VS 8.5 -and by resource limit exceeded callbacks. -.VE 8.5 -Note that the +and by resource limit exceeded callbacks. Note that the name space for files (such as the names returned by the \fBopen\fR command) is no longer shared between interpreters. Explicit commands are provided to share files and to transfer references to open files from one interpreter @@ -83,6 +81,7 @@ channels between interpreters. It can have any of several forms, depending on the \fIsubcommand\fR argument: .TP \fBinterp\fR \fBalias\fR \fIsrcPath\fR \fIsrcToken\fR +. Returns a Tcl list whose elements are the \fItargetCmd\fR and \fIarg\fRs associated with the alias represented by \fIsrcToken\fR (this is the value returned when the alias was @@ -90,6 +89,7 @@ created; it is possible that the name of the source command in the slave is different from \fIsrcToken\fR). .TP \fBinterp\fR \fBalias\fR \fIsrcPath\fR \fIsrcToken\fR \fB{}\fR +. Deletes the alias for \fIsrcToken\fR in the slave interpreter identified by \fIsrcPath\fR. \fIsrcToken\fR refers to the value returned when the alias @@ -97,6 +97,7 @@ was created; if the source command has been renamed, the renamed command will be deleted. .TP \fBinterp\fR \fBalias\fR \fIsrcPath\fR \fIsrcCmd\fR \fItargetPath\fR \fItargetCmd \fR?\fIarg arg ...\fR? +. This command creates an alias between one slave and another (see the \fBalias\fR slave command below for creating aliases between a slave and its master). In this command, either of the slave interpreters @@ -126,6 +127,7 @@ The command returns a token that uniquely identifies the command created does not have to be equal to \fIsrcCmd\fR. .TP \fBinterp\fR \fBaliases \fR?\fIpath\fR? +. This command returns a Tcl list of the tokens of all the source commands for aliases defined in the interpreter identified by \fIpath\fR. The tokens correspond to the values returned when @@ -133,16 +135,32 @@ the aliases were created (which may not be the same as the current names of the commands). .TP \fBinterp bgerror \fIpath\fR ?\fIcmdPrefix\fR? -.VS 8.5 -This command either gets or sets the current background error handler +. +This command either gets or sets the current background exception handler for the interpreter identified by \fIpath\fR. If \fIcmdPrefix\fR is -absent, the current background error handler is returned, and if it is +absent, the current background exception handler is returned, and if it is present, it is a list of words (of minimum length one) that describes -what to set the interpreter's background error to. See the -\fBBACKGROUND ERROR HANDLING\fR section for more details. -.VE 8.5 +what to set the interpreter's background exception handler to. See the +\fBBACKGROUND EXCEPTION HANDLING\fR section for more details. +.TP +\fBinterp\fR \fBcancel \fR?\fB\-unwind\fR? ?\fB\-\|\-\fR? ?\fIpath\fR? ?\fIresult\fR? +.VS 8.6 +Cancels the script being evaluated in the interpreter identified by +\fIpath\fR. Without the \fB\-unwind\fR switch the evaluation stack for +the interpreter is unwound until an enclosing catch command is found or +there are no further invocations of the interpreter left on the call +stack. With the \fB\-unwind\fR switch the evaluation stack for the +interpreter is unwound without regard to any intervening catch command +until there are no further invocations of the interpreter left on the +call stack. The \fB\-\|\-\fR switch can be used to mark the end of +switches; it may be needed if \fIpath\fR is an unusual value such +as \fB\-safe\fR. If \fIresult\fR is present, it will be used as the +error message string; otherwise, a default error message string will be +used. +.VE 8.6 .TP \fBinterp\fR \fBcreate \fR?\fB\-safe\fR? ?\fB\-\|\-\fR? ?\fIpath\fR? +. Creates a slave interpreter identified by \fIpath\fR and a new command, called a \fIslave command\fR. The name of the slave command is the last component of \fIpath\fR. The new slave interpreter and the slave command @@ -205,6 +223,7 @@ execution of all commands. .RE .TP \fBinterp\fR \fBdelete \fR?\fIpath ...?\fR +. Deletes zero or more interpreters given by the optional \fIpath\fR arguments, and for each interpreter, it also deletes its slaves. The command also deletes the slave command for each interpreter deleted. @@ -212,6 +231,7 @@ For each \fIpath\fR argument, if no interpreter by that name exists, the command raises an error. .TP \fBinterp\fR \fBeval\fR \fIpath arg \fR?\fIarg ...\fR? +. This command concatenates all of the \fIarg\fR arguments in the same fashion as the \fBconcat\fR command, then evaluates the resulting string as a Tcl script in the slave interpreter identified by \fIpath\fR. The result @@ -225,11 +245,13 @@ the slave that find out information about the slave's current state and stack frame. .TP \fBinterp exists \fIpath\fR +. Returns \fB1\fR if a slave interpreter by the specified \fIpath\fR exists in this master, \fB0\fR otherwise. If \fIpath\fR is omitted, the invoking interpreter is used. .TP \fBinterp expose \fIpath\fR \fIhiddenName\fR ?\fIexposedCmdName\fR? +. Makes the hidden command \fIhiddenName\fR exposed, eventually bringing it back under a new \fIexposedCmdName\fR name (this name is currently accepted only if it is a valid global name space name without any ::), @@ -240,6 +262,7 @@ fails. Hidden commands are explained in more detail in \fBHIDDEN COMMANDS\fR, below. .TP \fBinterp\fR \fBhide\fR \fIpath\fR \fIexposedCmdName\fR ?\fIhiddenCmdName\fR? +. Makes the exposed command \fIexposedCmdName\fR hidden, renaming it to the hidden command \fIhiddenCmdName\fR, or keeping the same name if \fIhiddenCmdName\fR is not given, in the interpreter denoted @@ -255,10 +278,12 @@ command, by making the current namespace be different from the global one. Hidden commands are explained in more detail in \fBHIDDEN COMMANDS\fR, below. .TP \fBinterp\fR \fBhidden\fR \fIpath\fR +. Returns a list of the names of all hidden commands in the interpreter identified by \fIpath\fR. .TP \fBinterp\fR \fBinvokehidden\fR \fIpath\fR ?\fI\-option ...\fR? \fIhiddenCmdName\fR ?\fIarg ...\fR? +. Invokes the hidden command \fIhiddenCmdName\fR with the arguments supplied in the interpreter denoted by \fIpath\fR. No substitutions or evaluation are applied to the arguments. Three \fI\-option\fRs are supported, all @@ -279,8 +304,13 @@ Note that the hidden command will be executed (by default) in the current context stack frame of the \fIpath\fR interpreter. Hidden commands are explained in more detail in \fBHIDDEN COMMANDS\fR, below. .TP +\fBinterp issafe\fR ?\fIpath\fR? +. +Returns \fB1\fR if the interpreter identified by the specified \fIpath\fR +is safe, \fB0\fR otherwise. +.TP \fBinterp\fR \fBlimit\fR \fIpath\fR \fIlimitType\fR ?\fI\-option\fR? ?\fIvalue\fR \fI...\fR? -.VS 8.5 +. Sets up, manipulates and queries the configuration of the resource limit \fIlimitType\fR for the interpreter denoted by \fIpath\fR. If no \fI\-option\fR is specified, return the current configuration of the @@ -288,13 +318,9 @@ limit. If \fI\-option\fR is the sole argument, return the value of that option. Otherwise, a list of \fI\-option\fR/\fIvalue\fR argument pairs must supplied. See \fBRESOURCE LIMITS\fR below for a more detailed explanation of what limits and options are supported. -.VE 8.5 -.TP -\fBinterp issafe\fR ?\fIpath\fR? -Returns \fB1\fR if the interpreter identified by the specified \fIpath\fR -is safe, \fB0\fR otherwise. .TP \fBinterp marktrusted\fR \fIpath\fR +. Marks the interpreter identified by \fIpath\fR as trusted. Does not expose the hidden commands. This command can only be invoked from a trusted interpreter. @@ -302,6 +328,7 @@ The command has no effect if the interpreter identified by \fIpath\fR is already trusted. .TP \fBinterp\fR \fBrecursionlimit\fR \fIpath\fR ?\fInewlimit\fR? +. Returns the maximum allowable nesting depth for the interpreter specified by \fIpath\fR. If \fInewlimit\fR is specified, the interpreter recursion limit will be set so that nesting @@ -321,6 +348,7 @@ the maximum size of the C stack. .RE .TP \fBinterp\fR \fBshare\fR \fIsrcPath channelId destPath\fR +. Causes the IO channel identified by \fIchannelId\fR to become shared between the interpreter identified by \fIsrcPath\fR and the interpreter identified by \fIdestPath\fR. Both interpreters have the same permissions @@ -330,11 +358,13 @@ channels accessible in an interpreter are automatically closed when an interpreter is destroyed. .TP \fBinterp\fR \fBslaves\fR ?\fIpath\fR? +. Returns a Tcl list of the names of all the slave interpreters associated with the interpreter identified by \fIpath\fR. If \fIpath\fR is omitted, the invoking interpreter is used. .TP \fBinterp\fR \fBtarget\fR \fIpath alias\fR +. Returns a Tcl list describing the target interpreter for an alias. The alias is specified with an interpreter path and source command name, just as in \fBinterp alias\fR above. The name of the target interpreter is @@ -345,6 +375,7 @@ invoking interpreter or one of its descendants then an error is generated. The target command does not have to be defined at the time of this invocation. .TP \fBinterp\fR \fBtransfer\fR \fIsrcPath channelId destPath\fR +. Causes the IO channel identified by \fIchannelId\fR to become available in the interpreter identified by \fIdestPath\fR and unavailable in the interpreter identified by \fIsrcPath\fR. @@ -355,20 +386,24 @@ new Tcl command is created in the master interpreter with the same name as the new interpreter. This command may be used to invoke various operations on the interpreter. It has the following general form: +.PP .CS \fIslave command \fR?\fIarg arg ...\fR? .CE +.PP \fISlave\fR is the name of the interpreter, and \fIcommand\fR and the \fIarg\fRs determine the exact behavior of the command. The valid forms of this command are: .TP \fIslave \fBaliases\fR +. Returns a Tcl list whose elements are the tokens of all the aliases in \fIslave\fR. The tokens correspond to the values returned when the aliases were created (which may not be the same as the current names of the commands). .TP \fIslave \fBalias \fIsrcToken\fR +. Returns a Tcl list whose elements are the \fItargetCmd\fR and \fIarg\fRs associated with the alias represented by \fIsrcToken\fR (this is the value returned when the alias was @@ -376,12 +411,14 @@ created; it is possible that the actual source command in the slave is different from \fIsrcToken\fR). .TP \fIslave \fBalias \fIsrcToken \fB{}\fR +. Deletes the alias for \fIsrcToken\fR in the slave interpreter. \fIsrcToken\fR refers to the value returned when the alias was created; if the source command has been renamed, the renamed command will be deleted. .TP \fIslave \fBalias \fIsrcCmd targetCmd \fR?\fIarg ..\fR? +. Creates an alias such that whenever \fIsrcCmd\fR is invoked in \fIslave\fR, \fItargetCmd\fR is invoked in the master. The \fIarg\fR arguments will be passed to \fItargetCmd\fR as additional @@ -393,16 +430,16 @@ The command returns a token that uniquely identifies the command created does not have to be equal to \fIsrcCmd\fR. .TP \fIslave \fBbgerror\fR ?\fIcmdPrefix\fR? -.VS 8.5 -This command either gets or sets the current background error handler +. +This command either gets or sets the current background exception handler for the \fIslave\fR interpreter. If \fIcmdPrefix\fR is -absent, the current background error handler is returned, and if it is +absent, the current background exception handler is returned, and if it is present, it is a list of words (of minimum length one) that describes -what to set the interpreter's background error to. See the -\fBBACKGROUND ERROR HANDLING\fR section for more details. -.VE 8.5 +what to set the interpreter's background exception handler to. See the +\fBBACKGROUND EXCEPTION HANDLING\fR section for more details. .TP \fIslave \fBeval \fIarg \fR?\fIarg ..\fR? +. This command concatenates all of the \fIarg\fR arguments in the same fashion as the \fBconcat\fR command, then evaluates the resulting string as a Tcl script in \fIslave\fR. @@ -416,6 +453,7 @@ the slave that find out information about the slave's current state and stack frame. .TP \fIslave \fBexpose \fIhiddenName \fR?\fIexposedCmdName\fR? +. This command exposes the hidden command \fIhiddenName\fR, eventually bringing it back under a new \fIexposedCmdName\fR name (this name is currently accepted only if it is a valid global name space name without any ::), @@ -425,6 +463,7 @@ fails. For more details on hidden commands, see \fBHIDDEN COMMANDS\fR, below. .TP \fIslave \fBhide \fIexposedCmdName\fR ?\fIhiddenCmdName\fR? +. This command hides the exposed command \fIexposedCmdName\fR, renaming it to the hidden command \fIhiddenCmdName\fR, or keeping the same name if the argument is not given, in the \fIslave\fR interpreter. @@ -439,9 +478,11 @@ command, by making the current namespace be different from the global one. For more details on hidden commands, see \fBHIDDEN COMMANDS\fR, below. .TP \fIslave \fBhidden\fR +. Returns a list of the names of all hidden commands in \fIslave\fR. .TP \fIslave \fBinvokehidden\fR ?\fI\-option ...\fR? \fIhiddenName \fR?\fIarg ..\fR? +. This command invokes the hidden command \fIhiddenName\fR with the supplied arguments, in \fIslave\fR. No substitutions or evaluations are applied to the arguments. Three \fI\-option\fRs are supported, all @@ -463,10 +504,11 @@ For more details on hidden commands, see \fBHIDDEN COMMANDS\fR, below. .TP \fIslave \fBissafe\fR +. Returns \fB1\fR if the slave interpreter is safe, \fB0\fR otherwise. .TP \fIslave \fBlimit\fR \fIlimitType\fR ?\fI\-option\fR? ?\fIvalue\fR \fI...\fR? -.VS 8.5 +. Sets up, manipulates and queries the configuration of the resource limit \fIlimitType\fR for the slave interpreter. If no \fI\-option\fR is specified, return the current configuration of the limit. If @@ -474,15 +516,16 @@ is specified, return the current configuration of the limit. If Otherwise, a list of \fI\-option\fR/\fIvalue\fR argument pairs must supplied. See \fBRESOURCE LIMITS\fR below for a more detailed explanation of what limits and options are supported. -.VE 8.5 .TP \fIslave \fBmarktrusted\fR +. Marks the slave interpreter as trusted. Can only be invoked by a trusted interpreter. This command does not expose any hidden commands in the slave interpreter. The command has no effect if the slave is already trusted. .TP \fIslave\fR \fBrecursionlimit\fR ?\fInewlimit\fR? +. Returns the maximum allowable nesting depth for the \fIslave\fR interpreter. If \fInewlimit\fR is specified, the recursion limit in \fIslave\fR will be set so that nesting of more than \fInewlimit\fR calls to \fBTcl_Eval()\fR @@ -710,7 +753,6 @@ namespace even if the current namespace is not the global one. This prevents slaves from fooling a master interpreter into hiding the wrong command, by making the current namespace be different from the global one. .SH "RESOURCE LIMITS" -.VS 8.5 .PP Every interpreter has two kinds of resource limits that may be imposed by any master interpreter upon its slaves. Command limits (of type \fBcommand\fR) @@ -735,50 +777,46 @@ catch and handle. Every limit has a number of options associated with it, some of which are common across all kinds of limits, and others of which are particular to the kind of limit. -.VE 8.5 .TP \fB\-command\fR -.VS 8.5 +. This option (common for all limit types) specifies (if non-empty) a Tcl script to be executed in the global namespace of the interpreter reading and writing the option when the particular limit in the limited interpreter is exceeded. The callback may modify the limit on the interpreter if it wishes the limited -interpreter to continue executing. If the callback generates an error, it is -reported through the background error mechanism (see \fBBACKGROUND ERROR -HANDLING\fR). Note that the callbacks defined by one interpreter are +interpreter to continue executing. If the callback generates an exception, it +is reported through the background exception mechanism (see +\fBBACKGROUND EXCEPTION HANDLING\fR). +Note that the callbacks defined by one interpreter are completely isolated from the callbacks defined by another, and that the order in which those callbacks are called is undefined. -.VE 8.5 .TP \fB\-granularity\fR -.VS 8.5 +. This option (common for all limit types) specifies how frequently (out of the points when the Tcl interpreter is in a consistent state where limit checking is possible) that the limit is actually checked. This allows the tuning of how frequently a limit is checked, and hence how often the limit-checking overhead (which may be substantial in the case of time limits) is incurred. -.VE 8.5 .TP \fB\-milliseconds\fR -.VS 8.5 +. This option specifies the number of milliseconds after the moment defined in the \fB\-seconds\fR option that the time limit will fire. It should only ever be specified in conjunction with the \fB\-seconds\fR option (whether it was set previously or is being set this invocation.) -.VE 8.5 .TP \fB\-seconds\fR -.VS 8.5 +. This option specifies the number of seconds after the epoch (see \fBclock seconds\fR) that the time limit for the interpreter will be triggered. The limit will be triggered at the start of the second unless specified at a sub-second level using the \fB\-milliseconds\fR option. This option may be the empty string, which indicates that a time limit is not set for the interpreter. -.VE 8.5 .TP \fB\-value\fR -.VS 8.5 +. This option specifies the number of commands that the interpreter may execute before triggering the command limit. This option may be the empty string, which indicates that a command limit is not set for the interpreter. @@ -791,29 +829,32 @@ these conditions, it should hide the \fBinterp\fR command in the child and then use aliases and the \fBinterp invokehidden\fR subcommand to provide such access as it chooses to the \fBinterp\fR command to the limited master as necessary. -.SH "BACKGROUND ERROR HANDLING" +.SH "BACKGROUND EXCEPTION HANDLING" .PP -When an error happens in a situation where it cannot be reported directly up +When an exception happens in a situation where it cannot be reported directly up the stack (e.g. when processing events in an \fBupdate\fR or \fBvwait\fR call) -the error is instead reported through the background error handling mechanism. -Every interpreter has a background error handler registered; the default error +the exception is instead reported through the background exception handling mechanism. +Every interpreter has a background exception handler registered; the default exception handler arranges for the \fBbgerror\fR command in the interpreter's global -namespace to be called, but other error handlers may be installed and process -background errors in substantially different ways. +namespace to be called, but other exception handlers may be installed and process +background exceptions in substantially different ways. .PP -A background error handler consists of a non-empty list of words to which will +A background exception handler consists of a non-empty list of words to which will be appended two further words at invocation time. The first word will be the -error message string, and the second will a dictionary of return options (this -is also the sort of information that can be obtained by trapping a normal -error using \fBcatch\fR of course.) The resulting list will then be executed +interpreter result at time of the exception, typically an error message, +and the second will be the dictionary of return options at the time of +the exception. These are the same values that \fBcatch\fR can capture +when it controls script evaluation in a non-background situation. +The resulting list will then be executed in the interpreter's global namespace without further substitutions being performed. -.VE 8.5 .SH CREDITS The safe interpreter mechanism is based on the Safe-Tcl prototype implemented by Nathaniel Borenstein and Marshall Rose. .SH EXAMPLES +.PP Creating and using an alias for a command in the current interpreter: +.PP .CS \fBinterp alias\fR {} getIndex {} lsearch {alpha beta gamma delta} set idx [getIndex delta] @@ -821,32 +862,35 @@ set idx [getIndex delta] .PP Executing an arbitrary command in a safe interpreter where every invocation of \fBlappend\fR is logged: +.PP .CS set i [\fBinterp create\fR -safe] \fBinterp hide\fR $i lappend \fBinterp alias\fR $i lappend {} loggedLappend $i proc loggedLappend {i args} { - puts "logged invocation of lappend $args" - \fBinterp invokehidden\fR $i lappend {*}$args + puts "logged invocation of lappend $args" + \fBinterp invokehidden\fR $i lappend {*}$args } \fBinterp eval\fR $i $someUntrustedScript .CE .PP -.VS 8.5 Setting a resource limit on an interpreter so that an infinite loop terminates. +.PP .CS set i [\fBinterp create\fR] \fBinterp limit\fR $i command -value 1000 \fBinterp eval\fR $i { - set x 0 - while {1} { - puts "Counting up... [incr x]" - } + set x 0 + while {1} { + puts "Counting up... [incr x]" + } } .CE -.VE 8.5 .SH "SEE ALSO" -bgerror(n), load(n), safe(n), Tcl_CreateSlave(3) +bgerror(n), load(n), safe(n), Tcl_CreateSlave(3), Tcl_Eval(3), Tcl_BackgroundException(3) .SH KEYWORDS alias, master interpreter, safe interpreter, slave interpreter +'\"Local Variables: +'\"mode: nroff +'\"End: |