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Diffstat (limited to 'doc/dict.n')
| -rw-r--r-- | doc/dict.n | 34 |
1 files changed, 32 insertions, 2 deletions
@@ -4,7 +4,7 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: dict.n,v 1.18 2007/12/31 00:17:44 dkf Exp $ +'\" RCS: @(#) $Id: dict.n,v 1.19 2008/10/15 10:43:37 dkf Exp $ '\" .so man.macros .TH dict n 8.5 Tcl "Tcl Built-In Commands" @@ -23,33 +23,39 @@ below for a description), depending on \fIoption\fR. The legal \fIoption\fRs (which may be abbreviated) are: .TP \fBdict append \fIdictionaryVariable key \fR?\fIstring ...\fR? +. This appends the given string (or strings) to the value that the given key maps to in the dictionary value contained in the given variable, writing the resulting dictionary value back to that variable. Non-existent keys are treated as if they map to an empty string. .TP \fBdict create \fR?\fIkey value ...\fR? +. Create a new dictionary that contains each of the key/value mappings listed as arguments (keys and values alternating, with each key being followed by its associated value.) .TP \fBdict exists \fIdictionaryValue key \fR?\fIkey ...\fR? +. This returns a boolean value indicating whether the given key (or path of keys through a set of nested dictionaries) exists in the given dictionary value. This returns a true value exactly when \fBdict get\fR on that path will succeed. .TP \fBdict filter \fIdictionaryValue filterType arg \fR?\fIarg ...\fR? +. This takes a dictionary value and returns a new dictionary that contains just those key/value pairs that match the specified filter type (which may be abbreviated.) Supported filter types are: .RS .TP \fBdict filter \fIdictionaryValue \fBkey \fIglobPattern\fR +. The key rule only matches those key/value pairs whose keys match the given pattern (in the style of \fBstring match\fR.) .TP \fBdict filter \fIdictionaryValue \fBscript {\fIkeyVar valueVar\fB} \fIscript\fR +. The script rule tests for matching by assigning the key to the \fIkeyVar\fR and the value to the \fIvalueVar\fR, and then evaluating the given script which should return a boolean value (with the @@ -63,11 +69,13 @@ result. The key/value pairs are tested in the order in which the keys were inserted into the dictionary. .TP \fBdict filter \fIdictionaryValue \fBvalue \fIglobPattern\fR +. The value rule only matches those key/value pairs whose values match the given pattern (in the style of \fBstring match\fR.) .RE .TP \fBdict for {\fIkeyVar valueVar\fB} \fIdictionaryValue body\fR +. This command takes three arguments, the first a two-element list of variable names (for the key and value respectively of each mapping in the dictionary), the second the dictionary value to iterate across, @@ -82,6 +90,7 @@ normal \fBTCL_OK\fR result. The order of iteration is the order in which the keys were inserted into the dictionary. .TP \fBdict get \fIdictionaryValue \fR?\fIkey ...\fR? +. Given a dictionary value (first argument) and a key (second argument), this will retrieve the value for that key. Where several keys are supplied, the behaviour of the command shall be as if the result of @@ -90,20 +99,23 @@ supplied, the behaviour of the command shall be as if the result of subsequent) arguments. This facilitates lookups in nested dictionaries. For example, the following two commands are equivalent: .RS +.PP .CS dict get $dict foo bar spong dict get [dict get [dict get $dict foo] bar] spong .CE +.PP If no keys are provided, dict would return a list containing pairs of elements in a manner similar to \fBarray get\fR. That is, the first element of each pair would be the key and the second element would be the value for that key. - +.PP It is an error to attempt to retrieve a value for a key that is not present in the dictionary. .RE .TP \fBdict incr \fIdictionaryVariable key \fR?\fIincrement\fR? +. This adds the given increment value (an integer that defaults to 1 if not specified) to the value that the given key maps to in the dictionary value contained in the given variable, writing the @@ -112,6 +124,7 @@ are treated as if they map to 0. It is an error to increment a value for an existing key if that value is not an integer. .TP \fBdict info \fIdictionaryValue\fR +. This returns information (intended for display to people) about the given dictionary though the format of this data is dependent on the implementation of the dictionary. For dictionaries that are @@ -119,12 +132,14 @@ implemented by hash tables, it is expected that this will return the string produced by \fBTcl_HashStats\fR, similar to \fBarray info\fR. .TP \fBdict keys \fIdictionaryValue \fR?\fIglobPattern\fR? +. Return a list of all keys in the given dictionary value. If a pattern is supplied, only those keys that match it (according to the rules of \fBstring match\fR) will be returned. The returned keys will be in the order that they were inserted into the dictionary. .TP \fBdict lappend \fIdictionaryVariable key \fR?\fIvalue ...\fR? +. This appends the given items to the list value that the given key maps to in the dictionary value contained in the given variable, writing the resulting dictionary value back to that variable. Non-existent @@ -133,6 +148,7 @@ there to be no items to append to the list. It is an error for the value that the key maps to to not be representable as a list. .TP \fBdict merge \fR?\fIdictionaryValue ...\fR? +. Return a dictionary that contains the contents of each of the \fIdictionaryValue\fR arguments. Where two (or more) dictionaries contain a mapping for the same key, the resulting dictionary maps that @@ -140,6 +156,7 @@ key to the value according to the last dictionary on the command line containing a mapping for that key. .TP \fBdict remove \fIdictionaryValue \fR?\fIkey ...\fR? +. Return a new dictionary that is a copy of an old one passed in as first argument except without mappings for each of the keys listed. It is legal for there to be no keys to remove, and it also legal for @@ -147,6 +164,7 @@ any of the keys to be removed to not be present in the input dictionary in the first place. .TP \fBdict replace \fIdictionaryValue \fR?\fIkey value ...\fR? +. Return a new dictionary that is a copy of an old one passed in as first argument except with some values different or some extra key/value pairs added. It is legal for this command to be called with @@ -154,6 +172,7 @@ no key/value pairs, but illegal for this command to be called with a key but no value. .TP \fBdict set \fIdictionaryVariable key \fR?\fIkey ...\fR? \fIvalue\fR +. This operation takes the name of a variable containing a dictionary value and places an updated dictionary value in that variable containing a mapping from the given key to the given value. When @@ -161,9 +180,11 @@ multiple keys are present, this operation creates or updates a chain of nested dictionaries. .TP \fBdict size \fIdictionaryValue\fR +. Return the number of key/value mappings in the given dictionary value. .TP \fBdict unset \fIdictionaryVariable key \fR?\fIkey ...\fR? +. This operation (the companion to \fBdict set\fR) takes the name of a variable containing a dictionary value and places an updated dictionary value in that variable that does not contain a mapping for @@ -173,6 +194,7 @@ must be specified, but the last key on the key-path need not exist. All other components on the path must exist. .TP \fBdict update \fIdictionaryVariable key varName \fR?\fIkey varName ...\fR? \fIbody\fR +. Execute the Tcl script in \fIbody\fR with the value for each \fIkey\fR (as found by reading the dictionary value in \fIdictionaryVariable\fR) mapped to the variable \fIvarName\fR. There may be multiple @@ -189,6 +211,7 @@ does not use traces; changes to the \fIdictionaryVariable\fR's contents only happen when \fIbody\fR terminates. .TP \fBdict values \fIdictionaryValue \fR?\fIglobPattern\fR? +. Return a list of all values in the given dictionary value. If a pattern is supplied, only those values that match it (according to the rules of \fBstring match\fR) will be returned. The returned values @@ -196,6 +219,7 @@ will be in the order of that the keys associated with those values were inserted into the dictionary. .TP \fBdict with \fIdictionaryVariable \fR?\fIkey ...\fR? \fIbody\fR +. Execute the Tcl script in \fIbody\fR with the value for each key in \fIdictionaryVariable\fR mapped (in a manner similarly to \fBdict update\fR) to a variable with the same name. Where one or more @@ -229,7 +253,9 @@ and .QW "apple carrot apple banana" are equivalent dictionaries (with different string representations). .SH EXAMPLES +.PP Constructing and using nested dictionaries: +.PP .CS # Data for one employee \fBdict set\fR employeeInfo 12345-A forenames "Joe" @@ -263,6 +289,7 @@ foreach id [\fBdict keys\fR $employeeInfo] { .CE .PP A localizable version of \fBstring toupper\fR: +.PP .CS # Set up the basic C locale set capital [\fBdict create\fR C [\fBdict create\fR]] @@ -285,3 +312,6 @@ set upperCase [string map $upperCaseMap $string] append(n), array(n), foreach(n), incr(n), list(n), lappend(n), set(n) .SH KEYWORDS dictionary, create, update, lookup, iterate, filter +'\" Local Variables: +'\" mode: nroff +'\" End: |