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Boolean

Boolean = (False, True)

Example​

procedure SetReady(IsValid: Boolean; var Ready: Boolean);
begin
  Ready := IsValid and (not Ready);
end;

Usage​

Boolean represents Velox scripting's two logical values False and True with ordinals zero and one.

Additional Technical Info​

Boolean is the default PascalScript logical type. False has ordinal 0 and True has ordinal 1. Conditions, and, or, xor and not operate on logical values.

The two values have dedicated reference pages:

  • False represents an unsatisfied condition and has ordinal zero.
  • True represents a satisfied condition and has ordinal one.

Velox compiler behaviour

Velox's modified PascalScript compiler creates this built-in type with AddTypeS('Boolean', '(False, True)'). The values are therefore enum members supplied by the scripting language, not ordinary Velox-imported LongInt constants.

Velox also enables PascalScript's Boolean short-circuit option. When operands are Boolean, the right side of False and RightExpression and True or RightExpression is skipped because it cannot change the result. Do not place a required side effect in such a right-hand expression.

Do not use a Boolean as an undocumented integer flag or assume that any nonzero external value is automatically valid Boolean input. Native Delphi APIs also expose ByteBool, WordBool, LongBool and COM VARIANT_BOOL representations, but those are separate hidden/native interop types. Runtime importers are responsible for adapting them.

A Variant containing a Boolean is dynamically tagged; it is not the same as a statically typed Boolean variable. Test Null/Empty before converting a Variant to Boolean because conversion can raise or apply text/numeric conversion rules.

Use explicit Boolean names for configuration intent. When reading numeric/database flags, validate the accepted values and convert deliberately so invalid values are not silently treated as true.

The ordinal values overlap the Velox comparison-result constants: Same is numeric zero and MoreThan is numeric one. They are not Boolean aliases. Preserve the domain explicitly, especially when a Variant or external serialization no longer communicates the declared type.

The example is source-reviewed only; no script was executed.

External references

Created 2026-07-15