Syntax: Variables, Control Flow, Subprograms, and Tools

Variables and Assignments

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

Requirements to review:

• user variables such as R1
• system variables such as $P_ACT_X
• selector forms such as $A_IN[1], $P_UIFR[1,X,TR]
• assignment syntax:
  • R1 = 2
  • R1 = R2 + 1
  • R1 = $P_ACT_X + 1

Reviewed decisions:

• selector shapes required for now:
  • $NAME[<int>]
  • $NAME[<int>,<ident>]
  • $NAME[<int>,<ident>,<ident>]
• selector part rules for now:
  • first part must be a decimal integer
  • second and third parts, when present, must be identifiers [A-Za-z0-9_]+
• reject for now:
  • nested brackets
  • quoted strings in selectors
  • arithmetic expressions in selectors
  • empty selector parts
  • more than 3 selector parts
  • non-integer first selector part
• parenthesized subexpressions are wanted
• parentheses are for grouping in expressions and conditions, not comments
• general function-call-style expressions are not wanted for now
• command-specific special forms, if any, should be reviewed separately instead of being treated as general expression syntax

Control Flow Syntax

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

Families to review:

• labels
• GOTO, GOTOF, GOTOB, GOTOC
• IF cond GOTO ... [ELSE GOTO ...]
• structured IF / ELSE / ENDIF
• WHILE / ENDWHILE
• FOR / ENDFOR
• REPEAT / UNTIL
• LOOP / ENDLOOP

Review questions:

• full condition grammar wanted?
• AND, OR, and parentheses support?
• indirect or system-variable jump targets wanted?

Review note:

• family status is reviewed; the remaining questions should be converted into explicit accepted and rejected condition and target forms in a detailed pass

Subprogram Syntax

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

Families to review:

• direct subprogram call by name
• quoted-name subprogram call
• repeat count P
• RET
• M17
• ISO-compatible M98 P...
• PROC declaration forms

Examples:

• THE_SHAPE
• "THE_SHAPE"
• THE_SHAPE P2
• P=2 THE_SHAPE
• RET
• M17

Review note:

• family status is reviewed; declaration and call-shape details should be expanded from the already-reviewed naming rules above

Tool Syntax

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

Requirements to review:

• T<number>
• T=<number>
• T<n>=<number>
• management-on selector forms by location or name if wanted
• relationship to M6

Review note:

• family status is reviewed; mode-dependent selector shapes and M6 interaction still need detailed semantic follow-up