DynamicFunc class | dynfunc.h[75]

The DynamicFunc class is used to create new functions from source code strings dynamically at run-time. To create a new executable function, create a new DynamicFunc object:

local f = new DynamicFunc('function(x) { return x*2; }',
globals, locals, macros);

The first constructor argument is a string giving the source code to compile.

The optional second argument is a LookupTable containing the global symbols for the compilation. This can be the table returned from t3GetGlobalSymbols(), or it can be a custom table. The compiler looks up string keys in the table to resolve global symbol names; the corresponding values can be objects, properties, enum values, or function pointers.

The optional third argument is a StackFrameDesc object, or a list of StackFrameDesc objects, giving the stack frames to use for local variable access within the dynamic code. The source code can refer to local variables in these frames, and can assign new values to them. This is analogous to the way anonymous functions can refer to local variables in their lexically enclosing scopes. If you supply a list, the compiler searches the frames in order of their appearance in the list. If a variable appears in more than one frame in the list, the compiler will use the first occurrence it finds.

The optional fourth argument is a LookupTable giving the preprocessor macros to use for the compilation. This is a table in the format returned by t3GetGlobalsSymbols(T3PreprocMacros).

If the 'symtab' or 'macros' arguments are omitted or nil, the compilation is done without global symbols or macros, respectively. Note that built-in functions and intrinsic classes are identified by global symbols, so you won't be able to call any built-ins if you don't provide a symbol table.

The source code string can start with the keyword 'function', followed by a list of parameter names, followed by the executable statements in braces. Or, it can simply be a list of statements, in which case it's a function with no arguments, as though it started with 'function()'.

Creating a DynamicFunc compiles the source code. If a compilation error occurs (such as a syntax error, or an unknown symbol reference), the 'new' call will throw a CompilerException error. The exception object contains information on the specific compiler error.

To invoke the new function, simply use the standard function call syntax on the object value, as though it were a regular function pointer:

local y = f(7);

`intrinsic class DynamicFunc :`

Superclass Tree (in declaration order)

`DynamicFunc`

Subclass Tree

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Global Objects

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Summary of Properties

``

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Summary of Methods

`getSource`

Properties

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Methods

`getSource ( )` | `dynfunc.h[81]`

Get the original source code of the function. This returns the string that was used as the source string to create the function.

TADS 3 Library Manual
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