feature: multidimensional typed-constant arrays

• Type: feature (Track A — parser / const initializers)
• Status: DONE 2026-06-23 (commit e0fe418)

Resolution (2026-06-23)

const M: array[0..1,0..1] of integer = ((1,2),(3,4)) parses for global + routine-local consts; 2-D / 3-D / non-zero-based verified (1 2 3 4 / 10 30 40 60 / 1 4 5 8 / local 7 8 9 10). The const-array path adopted the var-section ND handling: comma-separated dims flatten to a 1-D row-major store with SymArrNDims/DimLo/DimSpan set (so M[i,j] reads via BuildFlatNDIndex). The nested ((..),(..)) initializer is consumed by a paren-depth walk and filled row-major; the flat-index writes lower identically to the single-flat-index reads BuildFlatNDIndex already emits. Front-end only; self-host byte-identical; make test green. Not pinned (no Track B request).

Test: test/test_multidim_const_array.pas.

(original below)

• Status (orig): backlog
• Found: 2026-06-23, differential sweep vs FPC
• Severity: low-medium (common for static lookup tables; a 1-D const + manual indexing is the workaround)

Gap

A multidimensional typed constant array does not parse:

const M: array[0..1,0..1] of integer = ((1,2),(3,4));

Expected: ], but got: (Kind: 80 = tkComma)

Two missing pieces:

1. Type bounds. ParseConstSection's typed-const array path (if CurTok.Kind = tkArray → cLo := ConstEval; '..'; cHi := ConstEval; Expect(']')) handles only a single [lo..hi]; the , of a second dimension trips the ] expectation. (The var-section/AllocArray path already supports array[a,b] via SymArrNDims/flattening — this path needs the same.)
2. Nested initializer. The const-array initializer loop is a flat repeat ParseInitVal until not Eat(','), so the nested ((1,2),(3,4)) form is unhandled. It needs to walk the parenthesised rows and flatten them into the pending-init element list in the same row-major order the multidim var layout uses (BuildFlatNDIndex).

Works today: 1-D typed const arrays (const A: array[0..2] of integer = (10,20,30)), and multidim var arrays with [i,j] indexing. Only the multidim const initializer combination is missing.

Workaround

Declare a 1-D const sized rows*cols and index M[r*cols + c], or use a var array filled at startup.

Repro

const M: array[0..1,0..1] of integer = ((1,2),(3,4)); begin writeln(M[0,0]); end. (FPC prints the table; pxx fails at the type bounds.)