# Structure Definition Embedding

> [HTML Version](structuredefinitionembedding.htm)

_Rewritten February 2022_

In order to bind a Dynamic Structure, the structure definition (i.e. the DEFSTRUCT) must be known at run time. This can be accomplished in one of two ways:

•	Call [MX\_DYNSTRUCT](mx_dynstruct.htm.md) (DYNOP\_INFO) to reprocess the DEFSTRUCT source code.

•	Arrange for the compiler to embed the desired DEFSTRUCT definitions into the RUN at compile time.

The first method is perhaps the most flexible, but has the disadvantage of requiring that the source code be available at run time. The second method increases the size of the RUN file somewhat, but has the advantage of eliminating the need for the source code at run time.

Structure definitions to be embedded may be identified by one of the following methods:

**Specifying individual structure definitions to be embedded:**

DEFSTRUCT st\_foo

    ...

ENDSTRUCT

\++pragma EMBED\_DEFSTRUCT st\_foo



Each EMBED\_DEFSTRUCT pragma identifies a single DEFSTRUCT, which must already have been seen by the compiler, for embedding.

**Enclosing a series of DEFSTRUCTs in a pair of EMBED\_DEFSTRUCT\_BEGIN and \_END pragmas: **

\++pragma EMBED\_DEFSTRUCT\_BEGIN

    ...

\++pragma EMBED\_DEFSTRUCT\_END



Any DEFSTRUCTs between the \_BEGIN and \_END pragmas will be embedded. You can have multiple such \_BEGIN and \_END blocks within a program.

**Implicit embedding:**

The .[BINDSTRUCT()](bindstruct.htm.md) statement will cause the definition of the referenced structure to be embedded. For example:

DEFSTRUCT ST\_FOO

    map2 tender,s,10

    ...

ENDSTRUCT

map1 ds, DYNSTRUCT

map1 bar, ST\_FOO



.BINDSTRUCT ds, bar    \! ST\_FOO definition will be embedded



In addition, any defined structure instance passed to a function which receives it as a DYNSTRUCT will be embedded.  Building on the above example, ...

bar.tender = "Joe"

call Fn'Dive(ds=bar)   \! ST\_FOO will be embedded (because of how fn'foo receives it)

...



function Fn'Dive(ds as DYNSTRUCT)

    ? "Hi , I'm "; ds.tender        \!  ds'tender = "Joe" (implicit binding)

endfunction



**History**

2022 February, A-Shell 6.5.1711, compiler edit 967:  Feature added to A-Shell.