C64-dev/newLang/planning/claims/E03-S06.md

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story: E03-S06 owner: e03_iface status: done started: 2026-11-09 depends-on: [E03-S02, E03-S04]

E03-S06 Claim

Intended change

Add src/compiler/interfaces.s, which runs once after the declaration pass. It numbers each interface method in source order in a new C_MEM_SLOT member column, then checks every class against every interface in its implements list. A satisfying method is public and has the same parameter count, parameter types, and return type; one method may satisfy identical requirements from several interfaces. Missing and private methods report E130, signature mismatches E131, a class method that matches a same-named requirement of another implemented interface E132, and an implements entry that names a class or program E133. All are reported at the class declaration line, column 1. The parser harness emits an $F9 slot record so a fixture can verify source order.

File area

• src/compiler/interfaces.s (new), src/compiler/parser.s
• src/common/parser.inc, src/common/diagcat.inc, docs/diagnostics.md
• tests/parser/parser-test.s, scripts/build-parser-test.ps1, scripts/verify-parser-test.ps1, scripts/demo-write-check.ps1
• tests/semantic/interfaces.n8, interfaces.expect, iface_bad.n8, iface_bad.expect, tests/parser/unknown.expect
• docs/architecture.md, docs/memory-map.md
• planning/claims/E03-S06.md
• generated files under build/

Acceptance evidence

• Interface method slots follow interface source order: interfaces.n8 declares Shape (area, scale, name), Named (label, show), and Display (show, declared after the class); the harness's $F9 record and interfaces.expect list them as shape 0/1/2, named 0/1, display 0. assign_slots writes that order into C_MEM_SLOT.
• A public exact-signature method satisfies a requirement: Box's five public methods match all five interface signatures exactly, and interfaces.n8 is accepted with no ERR file in the parser run.
• One method may satisfy identical requirements from multiple interfaces: Box's single public show() satisfies both Named.show() and Display.show(); no duplicate or conflict diagnostic is produced.
• Same-name incompatible requirements are rejected: iface_bad.n8 has Left (show()) and Right (show(x as byte)) implemented by one class whose show() matches Left; Right reports E132 at 49:1, SHOW HAS CONFLICTING SIGNATURES.
• Missing, private, parameter-mismatched, and return-mismatched methods each have fixture coverage: iface_bad.n8 expects E130 at 28:1 (AREA), E130 at 31:1 (LABEL, private), E131 at 37:1 (SCALE, word vs byte), and E131 at 43:1 (OK, word vs boolean). E133 at 54:1 covers a class used as an interface. All six exact diagnostics match their messages.

Coordination notes

• No other claim is active. E03-S05 is complete (42a26c9).
• Conformance legitimately adds E130 to tests/parser/unknown.n8 (Worker implements Printable without print); its exact expectation gained that first pass-1 line and still passes with six diagnostics.
• E132 and E133 extend the approved E130-E149 interface category; they do not change source syntax or the interface ABI. Slot order is spec 5.2's source order, and C_MEM_SLOT is parser metadata for later dispatch/MAP work.

Work log

• interfaces.s: assign_slots numbers interface methods by declaration; check_interfaces walks classes and implements lists in source order and reports at the class line. find_method ignores fields; a private method is treated as not implemented. same_sig compares result type, parameter count, and all parameter types. conflicting decides E132 by looking for a same-named requirement in another implemented interface whose signature the class method does satisfy. iface_err spells the argument from name_out and reports through diag_report, returning carry when the error limit stops compilation.
• parser.s exports tb_set, calls assign_slots then check_interfaces after layout_classes, and returns at once if the diagnostic limit is hit.
• parser.inc: C_MEM_SLOT = 26, TABLE_COLUMNS = 27; the parser tables are now 6,912 bytes in docs/memory-map.md.
• parser-test.s: dump_ifaces emits $F9, each interface name, member count, and each slot/name pair. Fixtures 40-41 added; FIXTURE_COUNT = 41.
• verify-parser-test.ps1: decodes $F9 before $FA, stops the type and member loops at it, treats the new iface group like an accepted fixture for diagnostics/member checks, and compares slot lines to interfaces.expect.
• diagcat.inc: E132 % HAS CONFLICTING SIGNATURES, E133 % IS NOT AN INTERFACE; catalog is 70 entries and docs are regenerated.
• First build failed on seven long bcs @stop/beq @inext branches in the 6502 code; each became a short branch plus jmp trampoline.

Completion

• Tests run: scripts/build-parser-test.ps1, scripts/verify-parser-test.ps1 -Port 6530, scripts/build-diag-test.ps1 -UpdateDocs, scripts/verify-diag-test.ps1 -Port 6530, scripts/verify-lexer-test.ps1 -Port 6530, scripts/demo-write-check.ps1 (good.n8 and bad.n8), scripts/demo-write-check.ps1 -Programs bad.n8.
• Results: all 41 parser fixtures pass (lowest expression SP $A7); interfaces.n8 reports 6 interface slots and 11 members that match the source oracle, and ifacebad.n8 matches all six exact diagnostics. The diagnostics catalog has 70 entries and its screen/ERR expectations and docs are in sync. The lexer still matches 10 fixtures / 6,733 bytes. The demo rebuilt and linked interfaces.s; good.n8 completed its Vim save and C128 check in the full run, and the bad.n8 rerun saved 258 PETSCII bytes identically and reported E151, E152, E120, and E061.
• Files changed: as listed under File area.
• Remaining risks: conformance positions are class-level (line, column 1) because member rows do not store a source column; the message names the method. E132 is anchored on a class method that matches another requirement; a class with no method at all still rejects each interface with E130. An implements entry naming no declared type is left to pass 2's unknown-name diagnostic, so E133 only covers declared classes/programs. The VICE verifier defaults on this machine (6532/6534/6535) can produce an empty monitor reply; all runs used -Port 6530. Interface dispatch tables and their MAP output remain E04/E05 work; C_MEM_SLOT is the stable input for them.