G-code Semantic Validation Requirements

This subtree collects non-syntax validation rules. These rules apply after text has been parsed into a structured form, but before execution.

Use this subtree for questions like:

• the text parses, but is it allowed?
• is a numeric value in range?
• are these words legal together?
• should this produce a warning or an error?

Review Status

Status values used in this subtree:

• Wanted
• Reviewed
• Deferred
• Rejected

Current state:

• Wanted: initial checklist extracted from current parser and semantic behavior +- not yet fully reviewed item-by-item

+## Semantic Validation Areas + +- Motion, Dwell, and Modal Validation +- Variables, Control Flow, and Subprogram Validation +- Diagnostics Policy and Classification + +## Scope Reminder + +- syntax requirements answer whether text can be parsed into structured form +- semantic requirements answer whether a parsed command, value, or combination

• is allowed +- execution requirements answer what should happen for valid input at runtime +EOF cat > docs/src/requirements/semantic/motion_dwell_and_modal_validation.md <<‘EOF’

Semantic: Motion, Dwell, and Modal Validation

Motion Command Validation

Status: Reviewed (2026-03-10 review pass)

Rules to review:

• G1 must not mix Cartesian and polar endpoint modes in one block
• G0 must not mix Cartesian and polar endpoint modes in one block, if that rule is desired consistently
• one conflicting motion-family command per block should produce a diagnostic
• arc-center words must match the effective working plane

Examples:

• valid: G1 X10 Y20 F100
• invalid: G1 X10 AP=90 RP=10
• invalid under G17: G2 X1 Y2 K3

Review note:

• family status is reviewed; detailed per-command invalid-combination rules still need to be expanded explicitly

Dwell Validation

Status: Reviewed (2026-03-10 review pass)

Rules to review:

• G4 must be in a separate block
• G4 requires exactly one dwell mode word
• G4 F... dwell value must be positive
• G4 S... dwell value must be positive
• non-numeric dwell values are invalid

Examples:

• valid: G4 F3
• valid: G4 S30
• invalid: G4 F-3
• invalid: G4 F3 S30
• invalid: G4
• invalid: G4 X10

Review note:

• family status is reviewed; exact diagnostic wording and severity still belong in the diagnostics-policy follow-up

Tool and Modal Validation

Status: Reviewed (2026-03-10 review pass)

Rules to review:

• invalid tool selector form by tool-management mode
• M6 with no pending tool selection policy classification
• invalid modal family conflicts inside one block
• duplicate modal codes in one block: warning, error, or allowed

Review note:

• family status is reviewed; duplicate-modal severity and tool-policy classification still need narrower rule text