HyperWork 2024 -二次开发-Tcl语言-括号与引号（7/12）

The example below illustrates that HyperWorks Desktop will not recognize arguments if they are not distinguished somehow:

set var1 HyperWorks uses Tcl and Tk;

In order to distinguish the arguments in a command string, you must use quotes or braces as shown in these examples:

set var1 "HyperWorks uses Tcl and Tk";
set var1 {HyperWorks uses Tcl and Tk};

Variables contained within quotes are always evaluated.

set var1 HyperWorks;
puts "$var1 uses Tcl and Tk";
HyperWorks uses Tcl and Tk

Since quotes do not have a right and a left, it is not possible to embed quotes within quotes directly. In the example below, HyperWorks Desktop interprets the quotes between "uses" and "tcl" as being the end quotes:

set var1 HyperWorks;
puts "$ HyperWorks uses "Tcl and Tk"";
extra characters after close-quote

Variables contained within braces are not evaluated.

set var1 HyperWorks;
puts {$var1 uses Tcl and Tk};
$var1 uses Tcl and Tk

Braces are very handy for program control. For example, you define a Tcl/Tk button that calls the command puts $var1 to return the most recent value of var1 when the button is pressed. The parameter for the button command will be {puts $var1} because you don’t want Tcl to evaluate $var1 when the button is defined, but instead when the button is pressed.

Square brackets run the commands contained within them.

set var1 HyperWorks;
set var2 [set var1];
puts $var2;
HyperWorks