Perry Money Language

Exact decimals. Every cent accounted for.

Perry is an English-style programming language for exact decimal calculations, created by Mzwandile Zulu. It is written in plain C and never uses floating point, so 0.1 + 0.2 is exactly 0.3, and every amount is rounded the way its currency requires.

never_changes_ VAT = 15%

rent     = 8500.00 ZAR
electric = 1250.50 ZAR
total    = rent + electric

show_me_results("Total:", total)
show_me_results("VAT:", vat_on_ total)

check_if_ total is_greater_than_ 9000.00 ZAR:
    show_me_results("Over budget")
since_then_:
    show_me_results("Within budget")

What you get

• Run with ▶ or F5. Output appears in the Perry panel; Shift+F5 stops the program. Programs that ask questions (ask_user_) run in the terminal so you can type answers.
• Mistakes underlined in red every time you save, and errors that happen while the program runs are underlined on the line that caused them.
• Perry Black, a black-and-gold colour theme: Command Palette → Preferences: Color Theme → Perry Black.
• The Perry spear icon on every .perry file.
• Highlighting for keywords, amounts (199.99 ZAR), percentages, dates, text and comments.
• Snippets: type check, try, define, npv, stats, lifetable, loan and more, then press Tab.

What Perry can do

• Amounts in different currencies that can't be mixed by accident, rounded to each currency's decimals (ZAR 2, JPY 0, KWD 3)
• split 100.00 ZAR into 3 always adds back up to exactly 100.00 ZAR
• Budgets, VAT, tax tables, loans and repayment schedules, simple and compound interest
• Reading CSV files, then filtering, sorting, grouping and saving reports
• Dates, business days and South African public holidays
• Double-entry bookkeeping that refuses entries that don't balance
• because_is_ explains how any value was worked out

For universities (Perry 0.9): 12 decimal places; engineering economics (npv_, irr_, payback_, depreciation schedules); actuarial maths (annuities, bond prices and yields, life tables); and statistics (standard_deviation_, median_, percentile_, correlation_, regression_). Every result is exact and rounded once, at the end.

Getting started

Perry is built from its C source code on your own computer the first time you use it. When you open a .perry file, the extension offers to Install PERRY. Click it and wait a few seconds, or run Perry: Install or Update PERRY from the Command Palette.

The extension uses the first PERRY it finds:

1. the Executable Path setting (perrylang.executablePath)
2. a PERRY you built, in your file's folder or a folder above it
3. the PERRY made by Install PERRY (in ~/.perry/bin)
4. PERRY on your PATH

Settings

Note

Perry is a calculation tool. Check important results, such as tax returns or loan agreements, with a qualified professional. Tax tables and holiday lists change, so keep your own up to date.

Perry is free and open source under the MIT licence. © 2026 Mzwandile Zulu.