Program Reference: Control Flow and Runtime

AilExecutor Control-Flow Examples

These examples describe the current AilExecutor runtime contract, not the current public ExecutionSession buffered-session behavior.

GOTO

Input:

N10 GOTO END
N20 G1 X10
END:
N30 G1 X20

Runtime effect in AilExecutor:

• parser lowers GOTO END and END: into control-flow instructions
• execution jumps to END
• N20 G1 X10 is skipped
• only N30 G1 X20 reaches the runtime as a move command

IF / ELSE / ENDIF

Input:

IF $P_ACT_X > 100
  G1 X0
ELSE
  G1 X10
ENDIF

Runtime effect in AilExecutor:

• the condition is evaluated at execution time, not parse time
• if $P_ACT_X > 100, only G1 X0 reaches the runtime
• otherwise only G1 X10 reaches the runtime

See Execution Workflow for the current ExecutionSession boundary and when to drop down to AilExecutor.

M Functions

Status:

• Partial (parse + validation + AIL emission + executor boundary policy)

Supported syntax:

• M<value>
• M<address_extension>=<value>

Validation:

• M value must be integer 0..2147483647
• extended form must use equals syntax
• extended form is rejected for predefined stop/end families:
  • M0
  • M1
  • M2
  • M17
  • M30

AIL output:

• emits m_function instructions with:
  • source
  • value
  • optional address extension

Executor boundary behavior:

• known predefined Siemens M values are accepted and advanced without machine actuation in v0
• unknown M values follow executor policy:
  • error
  • warning
  • ignore

Current limitation:

• runtime machine-function execution mapping is not implemented in this slice

Control Flow and Runtime

Implemented behavior:

• GOTO target search:
  • GOTOF: forward only
  • GOTOB: backward only
  • GOTO: forward then backward
  • GOTOC: same search as GOTO, unresolved target does not fault
• target kinds:
  • label
  • N line number
  • numeric line number
  • system-variable token target
• AilExecutor branch resolver contract:
  • injected resolver interface returns true, false, pending, or error
  • pending supports wait_token and retry timestamp
  • function/lambda overload remains as a compatibility adapter
• structured IF/ELSE/ENDIF lowering uses branch_if plus internal labels and gotos

Current limitations:

• loop-family statements remain parse-only
• live system-variable evaluation remains a runtime-resolver responsibility, not parser/lowering behavior