Xecute

The XECUTE command makes an entry in the GT.M invocation stack and executes the argument as GT.M code.

The format of the XECUTE command is:

X[ECUTE]:tvexpr expr[:tvexpr][,...]

An explicit or implicit QUIT within the scope of the XECUTE, but not within the scope of any closer DO, FOR, XECUTE or extrinsic, returns execution to the instruction following the calling point. This may be the next XECUTE argument or another command. At the end of the code specified by the XECUTE argument expression, GT.M performs an implicit QUIT.

Because XECUTE causes run-time compilation in GT.M, and because it tends to obscure code, use XECUTE only when other approaches clearly do not meet your particular requirement.

GT.M compiles XECUTE <literal> at compile time when the literal is valid GT.M code that has minimal impact on the M virtual machine. An XECUTE literal containing GOTO, NEW, QUIT, (nested) XECUTE and indirection can't be precompiled because of the interaction of those features with the stack architecture of the M virtual machine. Precompiled XECUTE literals do not show up in $STATCK() as having a separate stack level, but rather "disappear" into the stack level of the original XECUTE. Please observe the following cautions:

Note that indirection almost always performs better than an XECUTE that can't be precompiled. Note also that adding a QUIT at the end of an XECUTE that does not contain a FOR will leave it for run time compilation.

Examples of XECUTE

Example:

GTM>Xecute "Write ""HELLO"""
HELLO
GTM>

This demonstrates a simple use of Xecute.

Example:

Set x="" For Set x=$Order(^%x(x)) Quit:x=""  Xecute x

This $ORDER() loop XECUTEs code out of the first level of the global array ^%x. Note that, in most cases, having the code in a GT.M source file, for example TMPX.m, and using a Do ^TMPX improves efficiency.