${ } (Alias Interpreter)

A dollar sign followed by a pair of braces ( ${ } ) evaluates to a variety of values related to the specified user-named alias.

Text ${Alias} Text 
Text ${/d:Alias} Text 
Text ${/f:Alias} Text 
Text ${/n:Alias} Text 
Text ${/v:Alias} Text 

Parameters

Alias

Specifies the name of the alias to be expanded or evaluated. Alias must be a user-named alias or the Variable value used by the .foreach token.

/d

Evaluates to one or zero depending on whether the alias is currently defined. If the alias is defined, ${/v:Alias} is replaced by 1; if the alias is not defined, ${/v:Alias} is replaced by 0.

/f

Evaluates to the alias equivalent if the alias is currently defined. If the alias is defined, ${/f:Alias} is replaced by the alias equivalent; if the alias is not defined, ${/f:Alias} is replaced by an empty string.

/n

Evaluates to the alias name if the alias is currently defined. If the alias is defined, ${/n:Alias} is replaced by the alias name; if the alias is not defined, ${/n:Alias} is not replaced but retains its literal value of ${/n:Alias}.

/v

Prevents any alias evaluation. Regardless of whether Alias is defined, ${/v:Alias} always retains its literal value of ${/v:Alias}.

Additional Information

For an explanation of how to use aliases, see Using Aliases.

Remarks

If no switches are used and the alias is currently defined, ${Alias} is replaced by the alias equivalent. If no switches are used and the alias is not defined, ${Alias} always retains its literal value of ${Alias}.

One advantage of using the ${ } token is that the alias will be evaluated even if it is adjacent to other characters. Without this token, the debugger only replaces aliases that are separated from other tokens by a space.

As indicated, there are circumstances where the ${ } token is not replaced by anything but retains its literal value. This occurs when no switch is used and Alias is undefined, when the /n switch is used and Alias is undefined, and always when the /v switch is used. In these circumstances, the token retains its literal value, including the dollar sign and the braces. Therefore, if this is used as the parameter of a command, a syntax error will result, unless that parameter accepts arbitrary text strings.

There is, however, one exception to this. If you use ${/v:Alias} as the first parameter to the as (Set Alias) or aS (Set Alias) command, this token will be treated as the string Alias alone, not as the string ${/v:Alias}. This only works with the as, aS, and ad commands, and it only works when the /v switch is used—it will not work with ${/n:Alias} or ${Alias} when they retain their literal values.

Alias must be a user-named alias or the Variable value used by the .foreach token—not a fixed-name alias. If there is a fixed-name alias within the string Alias, it will be replaced before the ${ } token is evaluated.

 

 

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