# About `CENTURION` is the programming language for the modern roman. # Documentation ## Example code ### Hello World ``` DESIGNA x UT "Hello World!" DICE x ``` ### Recursive Fibonacci number function ``` DEFINI fib x UT { SI x EST NULLUS TUNC { REDI NULLUS } ALUID SI x EST I TUNC { REDI I } ALUID { REDI (INVOCA fib (x-II) + INVOCA fib (x-I)) } } ``` ### Number guessing game ``` VOCA FORS DESIGNA correct UT FORTIS_NUMERUS I C DESIGNA guess UT NULLUS DUM FALSITAS FACE { DESIGNA guess UT AUDI_NUMERUS SI guess MINUS correct TUNC { DICE "Too low!" } ALUID SI guess PLUS correct TUNC { DICE "Too high!" } ALUID { ERUMPE } } DICE "You guessed correctly!" ``` ## Variables Variables are set with the `DESIGNA` and `UT` keywords. Type is inferred. ``` DESIGNA x UT XXVI ``` Variable can consist of lower-case letters, numbers, as well as `_`. ## Data types ### NULLUS `NULLUS` is a special kind of data type in `CENTURION`, similar to the `null` value in many other languages. `NULLUS` can be 0 if evaluated as an int or float, or an empty string if evaluated as a string. `NULLUS` cannot be evaluated as a boolean. ### Strings Strings are written as text in quotes (`'` or `"`). ``` DESIGNA x UT "this is a string" ``` ### Integers Integers must be written in roman numerals using the following symbols: |Symbol|Value| |------|-----| |`I`|1| |`V`|5| |`X`|10| |`L`|50| |`C`|100| |`D`|500| |`M`|1000| Each of the symbols written by themself is equal to the value of the symbol. Different symbols written from largest to smallest are equal to the sum of the symbols. Two to three of the same symbol written consecutively is equal to the sum of those symbols (only true for `I`s, `X`s, `C`s or `M`s ). A single `I` written before a `V` or `X` is equal to 1 less than the value of the second symbol. Similarly, an `X` written before a `L` or `C` is 10 less than the second symbol, and a `C` written before a `D` or `M` is 100 less than the second symbol. Because of the restrictions of roman numerals, numbers above 3.999 are impossible to write in the base `CENTURION` syntax. If numbers of that size are required, see the `MAGNUM` module. The number 0 can be expressed with the keyword `NULLUS`. #### Negative numbers Negative numbers can be expressed as `NULLUS` minus the value. For an explicit definition of negative numbers, see the `SUBNULLA` module. ### Floats The base `CENTURION` syntax does not allow for floats. However, the `FRACTIO` module adds a syntax for fractions. ### Booleans Booleans are denoted with the keywords `VERITAS` for true and `FALSITAS` for false. ### Arrays Arrays are defined using square brackets (`[]`). ## Conditionals ### SI/TUNC If-then statements are denoted with the keywords `SI` (if) and `TUNC` (then). Thus, the code ``` DESIGNA x UT VERITAS SI x TUNC { DICE I REDI NULLLUS } DICE NULLUS > I ``` Will return `I` (1), as the conditional evaluates `x` to be true. ### Boolean expressions In conditionals, `EST` functions as an equality evaluation, and `MINUS` (<) and `PLUS` (>) function as inequality evaluation. ### ALUID When using `SI`/`TUNC` statements, you can also use `ALUID` as an "else". ``` DESIGNA x UT VERITAS SI x TUNC { DICE I } ALUID { DICE NULLUS } > I ``` `SI` statements may follow immediately after `ALUID`. ``` DESIGNA x UT II SI x EST I TUNC DICE I ALUID SI x EST II TUNC DICE II ALUID DICE III > II ``` ### Boolean operators The keyword `ET` can be used as a boolean "and". The keyword `AUT` can be used as a boolean "or". ``` DESIGNA x UT VERITAS DESIGNA y UT FALSITAS SI x ET y TUNC { DICE I } ALUID SI x AUT y TUNC { DICE II } ALUID { DICE III } > II ``` ## Loops ### DONICUM loops ``` DESIGNA x UT NULLUM DONICUM y UT NULLUM USQUE X FACE { DESIGNA x UT x + y } DICE x > XLV ``` ### DUM loops ``` DESIGNA x UT NULLUM DUM x PLUS X FACE { DESIGNA x UT x+I } DICE x > XI ``` ### PER loops ``` DESIGNA x UT [I, II, III, IV, V] PER y IN x FACE { DICE y } > I > II > III > IV > V ``` ## Functions Functions are defined with the `DEFINI` and `UT` keywords. The `REDI` keyword is used to return. `REDI` must have exactly one parameter. `REDI` can also be used to end the program, if used outside of a function. Calling a function is done with the `INVOCA` keyword. ``` DEFINI square x UT { REDI (x*x) } DICE (INVOCA square XI) > CXXI ``` ## Built-ins ### DICE ### AUDI ### AUDI_NUMERUS ### ERUMPE ### LONGITUDO ## Modules Modules are additions to the base `CENTURION` syntax. They add or change certain features. Modules are included in your code by having ```VOCA %MODULE NAME%``` In the beginning of your source file. Unlike many other programming languages with modules, the modules in `CENTURION` are not libraries that can be "imported" from other scripts written in the language. They are features of the compiler, disabled by default. ### FORS ```VOCA FORS``` The `FORS` module allows you to add randomness to your `CENTURION` program. It adds 2 new built-in functions: `FORTIS_NUMERUS int int` and `FORTIS_ELECTIONIS ['a]`. `FORTIS_NUMERUS int int` picks a random int in the (inclusive) range of the two given ints. `FORTIS_ELECTIONIS ['a]` picks a random element from the given array. `FORTIS_ELECTIONIS array` is identical to ```array[FORTIS_NUMERUS NULLUS ((LONGITUDO array)-I)]```. ### FRACTIO ```VOCA FRACTIO``` The `FRACTIO` module adds floats, in the form of base 12 fractions. In the `FRACTIO` module, `.` represents 1/12, `:` represents 1/6 and `S` represents 1/2. The symbols must be written from highest to lowest. So 3/4 would be written as "`S:.`". Fractions can be written as an extension of integers. So 3.5 would be "`IIIS`". The symbol `|` can be used to denote that the following fraction symbols are 1 "level down" is base 12. So after the first `|`, the fraction symbols denote 144ths instead of 12ths. So 7 and 100/144 would be "`VIIS:|::`", as "7 + 100/144" is also "7+9/12+4/144". A single "set" of fraction symbols can only represent up to 11/12, as 12/12 can be written as 1. ### MAGNUM ```VOCA MAGNUM``` `MAGNUM` adds the ability to write integers larger than `MMMCMXCIX` (3.999) in your code, by adding the thousands operator, "`_`". When `_` is added _after_ a numeric symbol, the symbol becomes 1.000 times larger. The operator can be added to the same symbol multiple times. So "`V_`" is 5.000, and "`V__`" is 5.000.000. The strict rules for integers still apply, so 4.999 cannot be written as "`IV_`", but must instead be written as "`MV_CMXCIX`". All integer symbols except `I` may be given a `_`. ### SUBNULLA ```VOCA SUBNULLA``` The `SUBNULLA` module adds the ability to write negative numbers as `-II` instead of `NULLUS-II`.