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Type Naming in LiveCode Builder

Copyright 2015 LiveCode Ltd.

Introduction

The Builder standard library introduces a large number of types. These types require a consistent naming convention, in order to clearly indicate where the types come from and what they are intended to be used for.

Some of the types listed in this document will not be available immediately; however, they may be implemented in the future.

Mixed-case naming

The current Builder compiler cannot recognise any symbol that is also used in syntax. So, for example, it is not possible to define a variable called last because last is already used as a keyword in syntax such as:

the last offset of <Needle> in <Haystack>

There are a small number of types that are compiler built-in types and can therefore safely have a lower-case name (e.g. string and list), but this is an implementation detail and might change.

Types in the Builder standard library should therefore have mixed-case names.

For consistency with the LiveCode naming conventions used elsewhere, types should have title-case names.

Universal types

There are some universal, fundamental types that are independent of development platform and programming language. These do not use a platform prefix.

  • Pointer: A memory address.

  • UInt<BITS>: An unsigned integer represented using the specified number of bits (e.g. UInt32).

  • Int<BITS>: A signed integer represented using the specified number of bits (e.g. Int8).

  • IntSize, UIntSize: An (unsigned) integer representing a memory extent (e.g. the length of a buffer). This is used whenever a number that's proportional to the size of memory is required. On most platforms, its size will be equal to the size of a Pointer.

  • IntPointer, UIntPointer: An (unsigned) integer with the same number of bits as a Pointer.

  • Float<BITS>: A IEEE-754 binary floating point value represented using the specified number of bits (e.g. Float32).

  • Float<BITS>Dec: A decimal floating point value represented using the specified number of bits (e.g. Float32Dec).

LiveCode Core types

The Builder language standard library provides a small number of "core" types that are central to the programming language and will be used by any Builder program. Like the universal types, these do not use a platform prefix.

  • String

  • List

  • Number, Integer and Real

  • Boolean

C types

For foreign function calls into C libraries, some C-specific fundamental types are required. These use the C platform prefix.

  • CBool: C's bool type (stdbool.h).

  • CInt: C's int type.

  • CUInt: C's unsigned int type.

  • CFloat: C's float type.

  • CDouble: C's double type.

LiveCode library types

For foreign function calls into the LiveCode engine's C/C++ libraries, some special foreign types are required.

  • LCIndex, LCUIndex: Indices (e.g. into lists or strings)

  • LCInt, LCUInt: Integers

String buffers

Many applications require nul-terminated string buffers.

  • ZStringNative: Nul-terminated string buffer containing compact character data with 8 bits per character.

  • ZStringUTF8: Nul-terminated string buffer containing UTF-8 character data.

  • ZStringUTF16: Nul-terminated string buffer containing UTF-16 character data.