⬡ Serez Packages

serez-cobol

v2.0.2

Bidirectional COBOL <-> Serez (.sz) source-to-source translator, written in pure .sz.

by serezdev · published 2026-07-04

serez-cobol

A bidirectional COBOL ⇄ Serez (.sz) source-to-source translator for Serez-Code, written in pure .sz. It turns a COBOL program into an equivalent Serez-Code program that runs on the sz interpreter — and can translate the generated .sz back to COBOL.

The core's exact dec type is what makes COBOL's fixed-point arithmetic (PIC 9V99, COMPUTE … ROUNDED) faithful — a banking calculation translates without binary rounding drift:

COMPUTE WS-TAX = WS-SUBTOTAL * 0.21 ROUNDED.

becomes

WS_TAX = ((WS_SUBTOTAL * 0.21m) + 0m).setScale(2, "half-up");

Install & use

sz install serez-cobol

The package exposes a single convert command via sz run — it decides the direction from the file extension, there are no sub-commands:

sz run convert program.cob    # COBOL → Serez: writes program.sz
sz run convert program.sz     # Serez → COBOL: writes program.cob
sz program.sz                 # run the translated program

Free-format and fixed-format sources are auto-detected; COPY copybooks resolve next to the source file.

What it covers

The forward direction handles the working set of a real COBOL program: DATA / PROCEDURE divisions, PIC types (numeric-edited included), OCCURS tables, level-88 condition names, arithmetic with ROUNDED, IF / EVALUATE (including ALSO decision tables), every PERFORM form (THRU, TIMES, UNTIL, VARYING … AFTER), unstructured control flow (GO TO, GO TO … DEPENDING ON, ALTER — paragraphs run under a program-counter driver so spaghetti COBOL behaves exactly like COBOL), CALL to same-file subprograms, string handling (STRING, UNSTRING, INSPECT, reference modification) and LINE SEQUENTIAL file I/O.

The reverse direction reads //@ annotations that the forward pass embeds in the generated .sz (a source map of the IDENTIFICATION / ENVIRONMENT / DATA divisions) and genuinely re-translates the procedure. A COBOL → .sz → COBOL → .sz round-trip preserves behavior (same output), though not byte-identical text — ADD 1 TO X comes back as COMPUTE X = X + 1.

Main gaps: REDEFINES / COMP-3 byte layouts, SORT/MERGE, report writer, cross-file CALL.

Documentation

  • serez-cobol reference — supported statements, type mapping, round-trip semantics and worked examples, on the Serez-Code site.

Tests

sz tests/run_tests.sz         # translate + run + diff vs golden (end-to-end)
sz tests/run_roundtrip.sz     # COBOL→sz→COBOL→sz, verifies behavior is preserved

Every examples/<name>.cob is translated, executed, and compared against its examples/<name>.expected golden; the round-trip runner then verifies the full cycle on the same examples.

Layout

index.sz             single entry point (routes by file extension)
cobol.sz             the COBOL→sz engine (lexer + parser + emitter + COPY)
serez.sz             the sz→COBOL engine (reverse; reads //@ annotations)
runtime/cobol_rt.sz  PIC-editing + class-test runtime, prepended when needed
examples/            sample COBOL programs, copybooks and golden outputs
tests/               end-to-end + round-trip runners (pure .sz)