A debugging graph element wrapping an action function. Warning: Cannot be serialized.

Delays a trigger by a given amount of time. If a new trigger input arrives before the delay has expired, the previous trigger is cancelled and the delay is rescheduled.

The representation of a folder within an expression program. It allows to refer to existing folders through "key".attr[Folder] or to create a prototype Folder() which has a make action.

Note: passing a folder with runWith is not yet implemented.

Beginning of a conditional block.

Latches the expression based on the trigger argument. The initial state of the returned expression corresponds to the initial state of the input expression. Subsequent values are updated and cached only when a trigger occurs.

A random number generator that can be used for operations such as .until and .range.

Example:

val gen = Random()
val r100 = gen.until(100)
Act(
  r100, // draw new number between 0 and 99
  PrintLn("Random number: " ++ r100.toStr)  // print current value
)

Applies 'printf' style formatting.

The template string may contain fixed text and one or more embedded format specifiers. Consider the following example:

val n   = "name".attr[String]("?")
val tmp = "Duke's name: %1$s!"
PrintLn(tmp.format(n))

The template contains one format specifier "%1$s" which indicates how the argument should be processed and where it should be inserted in the text. The remaining portions of the template string are fixed text including "Duke's name: " and "!".

The argument list consists of all arguments passed to the formatter. In the above example, the argument list is of size one and consists of the string expression object n.

• The format specifiers for general, character, and numeric types have the following syntax:

%[argument_index$][flags][width][.precision]conversion

The optional argument_index is a decimal integer indicating the position of the argument in the argument list. The first argument is referenced by "1$", the second by "2$", etc.

The optional flags is a set of characters that modify the output format. The set of valid flags depends on the conversion.

The optional width is a positive decimal integer indicating the minimum number of characters to be written to the output.

The optional precision is a non-negative decimal integer usually used to restrict the number of characters. The specific behavior depends on the conversion.

The required conversion is a character indicating how the argument should be formatted. The set of valid conversions for a given argument depends on the argument's data type.

• The format specifiers which do not correspond to arguments have the following syntax:

%[flags][width]conversion

The optional flags and width is defined as above.

The required conversion is a character indicating content to be inserted in the output.

Conversions

Conversions are divided into the following categories:

• General - may be applied to any argument type
• Numeric
• Integral - may be applied to integral types such as: Int and Long.
• Floating Point - may be applied to the floating-point type Double.
• Percent - produces a literal '%'
• Line Separator - produces the platform-specific line separator

The following table summarizes the supported conversions. Conversions denoted by an upper-case character (i.e. 'B', 'H', 'S', 'C', 'X', 'E', 'G', 'A', and 'T') are the same as those for the corresponding lower-case conversion characters except that the result is converted to upper case.

A trigger element.

Important: Implementation inadvertently run into trouble if they do not extend Trig.Lazy to avoid "splitting" of the event paths. The only reason this is not enforced is that implementation may already mixin lazy traits such as Control (and by extension, Widget).