ZBasic Language Reference
76
ZBasic Microcontrollers
#if <expression>
<other-text>
#elseif <expression>
<other-text>
#else
<other-text>
#endif
The <expression> element may be any legal ZBasic expression involving constants, conditional
identifiers, ZBasic operators and ZBasic System Library functions that can be evaluated at compile time.
The usual type-compatibility rules apply, e.g., you cannot add an integral value and a string value.
Additionally, the special operator defined() may be used in a conditional expressions. The parameter
to the defined() operator should be an identifier and the result will be non-zero or zero depending on
whether the identifier is defined or not.
Examples
#if defined(EXPERIMENTAL)
Debug.Print "Experimental version"
#endif
#if defined(Pin.RedLED)
Call PutPin(Pin.RedLED, zxOutputLow)
#endif
The #elseif clause in the conditional construction may appear zero or more times. The #else clause
may appear at most once. The <other-text> element represents arbitrary text and may contain other
conditional constructs. There is no practical limit on the nesting of conditionals.
Examples
#if Version >= 23
#ifdef EXPERIMENTAL
' prepare the external circuitry and activate it
Call TestSetup(i)
Call PutPin(12, j)
#endif
#endif
#if (Version >= 23) And (EXPERIMENTAL <> 0)
' prepare the external circuitry and activate it
Call TestSetup(i)
Call PutPin(12, j)
#endif
The two examples above have the same effect.
Conditional identifiers may be used in definitions, statements, and expressions as if they were constants
defined using the Const definition (but the converse is not true).
#define Version "V1.0"
#define arraySize 26
Dim myArray(1 To arraySize) as Byte
debug.print Version
One implication of this is that adding a definition of a conditional identifier may result in a compiler
message related to a Const definition warning about duplicate definitions. Conditional identifiers defined
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