nes-pascal

Enumeration Implementation and Measurements (0.5.9)

English

Milestone 0.5.9 adds user-defined, nominal, byte-sized enumeration types. EnumType preserves type identity, ordered member names, and their deterministic underlying byte values through semantic analysis. Enum members become typed compile-time immediates; there is no runtime enum subsystem.

Lowering and storage

The only syntax is type Name = (Member, ...);; members are unqualified.
The first member is $00, followed by sequential byte values through $FF.
Variables use one ordinary scalar byte and are eligible for the existing promotion policy. Members, type declarations, descriptors, and tables consume no RAM, ROM, or Zero Page.
Nominal type identity remains intact until ca65 lowering. Cross-enum and enum/scalar assignments or equality comparisons are rejected.
Equality and inequality use the direct-immediate/direct-memory machinery from 0.5.7. A branch-only comparison does not materialize a Boolean result.

Representative lowering for if State = Playing then is:

    lda variable_State
    cmp #$01
    beq @if_then_0

Enumeration benchmark

The enumerations workload performs title, playing, pause, and game-over state transitions, enum copies, equality, inequality, stored Boolean results, and a branch-only comparison.

Metric	Result
PRG code	275 B
PRG occupied	281 B
Instructions	125
Estimated static base cycles	408
Expression tree depth	1
Maximum live expression temporaries	0
Temporaries actually required	0 B
Enum user storage	3 B (1 B promoted ZP, 2 B regular RAM)
ZP benchmark allocated/reserved	26 B
ZP allocator-visible free	127 B
Regular allocator-visible free	1,530 B
Runtime features	None

The 17 pre-existing workloads (minimal through arrays and gameplay_full_stack) remain byte-for-byte identical in all reported benchmark metrics. Programs without an enum declaration add no enum code, runtime state, RAM, Zero Page, ROM metadata, or descriptors.

Deliberately deferred

Enum arithmetic, inc/dec, ordering, explicit numeric values, bit flags, sets, arrays of enums, procedure enum parameters, enum constants in const, reflection, serialization, records, and runtime metadata remain outside this milestone.

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