Principal Compiler Engineer, COBOL Front End

What you will do

• Extend the COBOL grammar and preprocessor for COPY REPLACING, nested copybooks, compiler directives (CBL/PROCESS) and dialect switches between Enterprise COBOL 4.2, 6.x and Micro Focus.
• Keep the storage-layout engine byte-accurate for REDEFINES, OCCURS DEPENDING ON, COMP, COMP-3, COMP-5 and SIGN SEPARATE, with regression suites built from real compiler listings.
• Model EXEC CICS and EXEC SQL blocks as typed AST nodes so symbol resolution can follow COMMAREAs, BMS map fields and host variables.
• Design error recovery so a 40,000-line program with three unknown vendor extensions still yields a usable AST and a precise list of what was skipped.
• Review parser changes from the dialect team and set the bar for test coverage on every grammar production.

What we are looking for

• 8+ years building compilers, interpreters or static analysis tools in production, with at least one hand-written or generated parser you maintained for years.
• Working knowledge of COBOL data division semantics: level numbers, PICTURE clauses, USAGE, 88-level condition names, and how the compiler lays them out in storage.
• Strong Java or Kotlin (our parser services) and comfort reading grammar tooling such as ANTLR or a recursive-descent equivalent.
• Habit of writing the failing test before the fix, and of reading compiler listings to settle arguments.

Nice to have

• Experience with IBM Enterprise COBOL compiler options (ARITH, TRUNC, NUMPROC) and their effect on arithmetic results.
• PL/I, Assembler or Natural parsing experience.
• Contributions to open-source language tooling.

Where you will work

This role is based at our Mumbai office, with flexible hours and up to two remote days a week. Office: 14 Floor-1 Plot-199, Maria Bhuvan P Dmello Rd, Mumbai G.P.O., Mumbai, Maharashtra 400001, India.