L6: Bool type for DVM-BASIC (fixes #114, stacks on #111) by liqdmetal · Pull Request #115 · DEROFDN/derohe

liqdmetal · 2026-08-23T21:55:09Z

Summary

L6 from the DVM-BASIC language agenda (P2): a real boolean type — DIM b AS Bool, built-in TRUE/FALSE constants, boolean assignment from comparisons, logical && / || / !, and Bool function parameters.

The syntax

DIM b AS Bool
LET b = TRUE
LET b = FALSE
LET b = (x > 3)          ' comparison -> 0/1
IF b && (y < 10) THEN ...
IF !(b == FALSE) THEN ...
Function Pass(flag Bool) Uint64 ...

Implementation

Bool = Vtype 0x6, stored internally as uint64 0/1 — fully compatible with the existing comparison/IF semantics (which already return 0/1), so no breaking change
check_valid_type("bool") + every type-switch site extended (DIM, LET, eval Ident, arrays, function params, CONST resolution)
TRUE/FALSE seeded as Bool-typed constants per interpreter run — they resolve through the L7 CONST path (which gained a Bool case)
Gated >= 10.0.0 like the rest of the L-series

Tests (`dvm/control_flow_l6_test.go`, 4 cases)

Test	Verifies
`TestL6_BoolBasics`	TRUE/FALSE constants + comparison assignment
`TestL6_BoolLogic`	`&&` / `
`TestL6_BoolParam`	Bool function parameter
`TestL6_VersionGate`	Bool at 1.2.3 rejected

Full dvm suite green (29 control-flow tests).

Relationship

Stacks on L7+L8 (PR L7+L8: CONST named constants + enforced version gate (fixes #110, stacks on #109) #111) — uses the CONST resolution path for TRUE/FALSE
L-series now 7/10 delivered (L1–L4, L6, L7, L8); remaining: L5 (multi-value returns), L9 (signed ints), L10 (block scoping)

Branch: feature/dvm-l6-bool in the fork liqdmetal/derohe-improvements-by-liqdmetal (stacked on feature/dvm-l7-l8-const-version).

…F/ELSE/ENDIF Replaces GOTO-only spaghetti with structured loops and blocks (spec dero-improvements-agenda.md L1, P0). Halves contract size, cuts the len(scdata)*1.5 code-size fee term, makes contracts auditable. New dvm/control_flow.go: - FOR var = start TO end [STEP step] / NEXT var — counter loop, step default 1, nested frames via the interpreter's Loops stack - WHILE expr / WEND — pre-tested loop, jumps back to the WHILE line - block IF expr THEN ... [ELSE ...] ENDIF — detected as the line ending in THEN without GOTO (existing single-line IF THEN GOTO untouched) - LoopFrame stack on DVM_Interpreter for nesting (FOR-in-WHILE verified) - findMatchingLine scans forward for WEND/ENDIF respecting nesting Consensus-safety: - ALL new keywords gated on DVM version >= 10.0.0 (contract must call version("10.0.0")); pre-fork contracts cannot accidentally use them - no parser changes — the line-token interpreter dispatches the new keywords natively Tests (dvm/control_flow_test.go, 8 cases): - FOR/NEXT sum(1..5)=15, FOR/STEP 0+2+4=6, WHILE countdown=10 iterations, block IF/ELSE both branches, IF-no-ELSE fall-through, nested FOR-in-WHILE total=9, version gate (1.2.3 rejected), no-version gate (0.0.0 rejected) Full dvm suite green, whole tree builds.

…F/ELSE/ENDIF Replaces GOTO-only spaghetti with structured loops and blocks (spec dero-improvements-agenda.md L1, P0). Halves contract size, cuts the len(scdata)*1.5 code-size fee term, makes contracts auditable. New dvm/control_flow.go: - FOR var = start TO end [STEP step] / NEXT var — counter loop, step default 1, nested frames via the interpreter's Loops stack - WHILE expr / WEND — pre-tested loop, jumps back to the WHILE line - block IF expr THEN ... [ELSE ...] ENDIF — detected as the line ending in THEN without GOTO (existing single-line IF THEN GOTO untouched) - LoopFrame stack on DVM_Interpreter for nesting (FOR-in-WHILE verified) - findMatchingLine scans forward for WEND/ENDIF respecting nesting Consensus-safety: - ALL new keywords gated on DVM version >= 10.0.0 (contract must call version("10.0.0")); pre-fork contracts cannot accidentally use them - no parser changes — the line-token interpreter dispatches natively Tests (dvm/control_flow_test.go, 8 cases): FOR sum, FOR/STEP, WHILE countdown, block IF/ELSE, IF-no-ELSE fall-through, nested FOR-in-WHILE, version gate (1.2.3), no-version gate (0.0.0). All green. Also carries the build-manifest fix (go.mod/go.sum) for fresh-clone builds.

The second P0 language item (spec dero-improvements-agenda.md L2): internal subroutines so entrypoints stop re-implementing helpers. GOSUB <line>: pushes the return address (the line after the GOSUB) onto the interpreter's CallStack and jumps to <line>. RETURN: when CallStack is non-empty, pops it and jumps back (subroutine return — value ignored, subroutines communicate via shared Locals); otherwise behaves exactly as today (function return). Fully backward-compatible: existing contracts never push a CallStack. Gated on DVM version >= 10.0.0 like L1 (contract must call version("10.0.0")). Nests correctly (GOSUB-in-GOSUB, GOSUB-in-FOR). Tests (dvm/control_flow_l2_test.go, 5 cases): - TestL2_Gosub: shared-Locals helper (x*2) - TestL2_NestedGosub: 1 + 10 = 11 via nested calls - TestL2_GosubInFor: helper inside FOR body, 1+2+3 = 6 - TestL2_FunctionReturnStillWorks: plain RETURN unaffected - TestL2_VersionGate: GOSUB at 1.2.3 rejected Stacks on L1 (feature/dvm-l1-control-flow-pr, PR DEROFDN#101).

First-class array semantics for DVM-BASIC (spec dero-improvements-agenda.md L3, P1): DIM a(n) AS Uint64|String creates a zero-filled RAM array (indices 0..n, cap 1024); a[i] reads via the evaluator's new IndexExpr case; LET a[i] = expr writes (index may be a literal or expression like a loop variable); arrlen("a") returns the length. Design: - Variable gains Array *[]Variable (pointer keeps Variable comparable — it is used as a map key in RamStore/SC state) - Arrays are Locals-only: contracts cannot STORE an array (STORE takes scalars), so nothing touches the serialized SC state — consensus-neutral - gated >= 10.0.0 like L1/L2 (contract must call version("10.0.0")) - composes with L1: FOR i = 0 TO n / a[i] = ... / NEXT i Tests (dvm/control_flow_l3_test.go, 4 cases): array basics (set/read/ arrlen), FOR-loop fill (sum of squares 0..10 = 385), string arrays, version gate (1.2.3 rejected). Full dvm suite green. Stacks on L2 (feature/dvm-l2-subroutines, PR DEROFDN#103).

mapkeys() -> String: comma-separated, sorted keys of the contract's state visible during execution (spec dero-improvements-agenda.md L4, P1). The effective key set is the union of: - RamStore: keys loaded from disk (via DiskLoader) during this call - RawKeys: keys written during this call (TX_Storage.RawKeys) Batch/paged contracts can now iterate their stored keys instead of hand-rolling key sets. The comma-separated String is the DVM-friendly return (intrinsics return String/Uint64); contracts split it, and L3 arrays give the next natural return type. Gated >= 10.0.0 like L1/L2/L3. Tests (dvm/control_flow_l4_test.go, 3 cases): key enumeration sorted/complete, batch iteration pattern, version gate (1.2.3 rejected). Full dvm suite green. Stacks on L3 (feature/dvm-l3-arrays, PR DEROFDN#107).

L7 (P2): CONST name = value declares an immutable named constant (uint64 or string literal) in the interpreter's Constants map. The evaluator resolves identifiers against Constants first; LET on a constant is rejected (immutability enforced). Declared inside a function, scoped to the interpreter run — Locals-only, consensus-neutral. L8 (P2): the version gate is now the enforced default — every new syntax keyword (L1-L4, CONST) requires version("10.0.0"); a contract with no version() call (0.0.0) or an old one (1.2.3) gets a hard rejection. Pre-fork contracts cannot accidentally use new syntax. Tests (dvm/control_flow_l7_test.go, 5 cases): CONST uint arithmetic (BASE*SCALE+1=301), CONST string concat+compare, CONST immutability (LET rejected), version gate (1.2.3), no-version gate (0.0.0). Full dvm suite green (25 control-flow tests incl. L1-L4 regression). Stacks on L4 (feature/dvm-l4-mapkeys, PR DEROFDN#109).

Adds a real boolean type to DVM-BASIC (spec dero-improvements-agenda.md L6, P2): DIM b AS Bool, built-in TRUE/FALSE constants, boolean assignment from comparisons, logical && / || / ! (existing evaluator ops), Bool function parameters. Design: Bool is Vtype 0x6, stored internally as uint64 0/1 — fully compatible with the existing comparison/IF semantics (which already return 0/1). check_valid_type("bool") + all the type-switch sites (DIM, LET, eval Ident, arrays, params, CONST resolution) extended. Gated >= 10.0.0 like the rest of the L-series. TRUE/FALSE seeded as Bool-typed constants per interpreter run (they resolve through the L7 CONST path, which needed a Bool case). Tests (dvm/control_flow_l6_test.go, 4 cases): Bool basics (TRUE/FALSE + comparison assignment), Bool logic (&& / || / !), Bool parameter, version gate (1.2.3 rejected). Full dvm suite green (29 control-flow tests). Stacks on L7+L8 (feature/dvm-l7-l8-const-version, PR DEROFDN#111).

…ndor) Same two fixes as the sibling PRs: remove the l.Operation.KickReader() calls (no published chzyer/readline implements it) and re-vendor with a proper modules.txt. Fresh-clone go build now succeeds without -mod=mod.

Pinned by TestWargameL6BoolNonCanonical: LET b = 2 silently stored 2 into a Bool-typed variable. A Bool holding 2 is truthy for IF/LAND/LOR (IsZero-based) but != TRUE (==1) — so b==TRUE was false while IF b was true: an inconsistent Boolean value. Now normalized: any non-zero uint64 assigned to a Bool becomes 1, zero becomes 0. Applied to both the LET path and the array-element Bool path. A Bool can never hold a non-canonical value again. Also documented the NOT boundary (bitwise ^ only in IF conditions, where it is branch-equivalent) — TestWargameL6BoolNot. Full dvm suite green.

liqdmetal · 2026-08-25T01:11:25Z

Superseded by PR #126 — the consolidated language package. Same code, one reviewable PR with no vendor noise.

liqdmetal added 7 commits August 23, 2026 14:53

This was referenced Aug 23, 2026

L9: signed integers for DVM-BASIC — Int type, negative literals #116

Open

L9: signed integers for DVM-BASIC (fixes #116, stacks on #115) #117

Closed

liqdmetal added 2 commits August 23, 2026 20:14

This was referenced Aug 25, 2026

DVM v10 language: structured control flow, subroutines, arrays, mapkeys, Bool, Int, CONST #125

Open

DVM v10 language: structured control flow, subroutines, arrays, mapkeys, Bool, Int, CONST (fixes #125) #126

Open

liqdmetal closed this Aug 25, 2026

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L6: Bool type for DVM-BASIC (fixes #114, stacks on #111) - #115

L6: Bool type for DVM-BASIC (fixes #114, stacks on #111)#115
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liqdmetal commented Aug 23, 2026

Summary

The syntax

Implementation

Tests (dvm/control_flow_l6_test.go, 4 cases)

Relationship

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liqdmetal commented Aug 25, 2026

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Tests (`dvm/control_flow_l6_test.go`, 4 cases)