1.  Util Macros

The Util macros are a collection of frequently used code. These all start with a star character *. Following are some of the more commonly used ones.

1.1  *catch

Eval with catch, displaying any errors as a warning. The warning message also contains the namespace (and proc if possible) of the offending call. When not running with wize -Wall, errors are silently ignored.

 *catch { CallFunc 1 "X" }

 # Equivalent to ...

 if {[catch { CallFunc 1 "X" } erc]} {
   .Warn "Catch: $erc"
 }

1.2  *value

Returns the value of a variable if it exists, otherwise returns the default, or if no default is given, an empty string, eg.

 set n [*value ::MyNs::Arr(Really_Long_Value) 0]

 # Equivalent to ...

 if {[info exists ::MyNs::Arr(Really_Long_Value)]} {
    set n $::MyNs::Arr(Really_Long_Value)
 } else {
    set n 0
 }

1.3  *bvalue

Return the value for an element from a binary (name/value pair) list. If available, the dict command is used, otherwise falls back to a list search.

 set LookupTable {able 1 baker 2 charlie 3}

 set val [*bvalue $LookupTable baker 0]

 # Equivalent to ...

 if {[dict exists $LookupTable baker]} {
   set val [dict get $LookupTable baker]
 } else {
   set val 0
 }

1.4  *fread/*fwrite

Read or write a file. Additional options are passed to fconfigure:

 set dat [*fread file1.dat]
 *fwrite file2.dat $dat -translation binary

 # Equivalent to ...

 set fp [open file1.dat]
 set dat [read $fp]
 close $fp

 set fp [open file2.dat w+]
 fconfigure $fp -translation binary
 if {[catch { puts -nonewline $fp $dat } erc]} {
   close $fp
   error $erc
 }
 close $fp

© 2008 Peter MacDonald