RPOS

RPOS is an (arguably) esoteric programming language made by User:iconmaster. It stands for Reverse Polish Operating System (or alternately, Reverse POlish Shell). It is a combination of RPL and DOS, as it has both a filesystem and a stack.

Description

RPOS takes a space-separated string of words. Each word can be either a number, a string (with ' or " prefixes), or a command. Numbers and strings are pushed onto the stack, commands are executed. Alternately, words can have a one-character symbol prefix; these prefixes change how the characters after are used. There are 3 basic data types: Numbers, strings, and directories. Numbers and strings may be pushed onto the stack; directories may not. Directories contain an associative array of data; the key is the variable's name, the value is that variable's value. The root directory and the starting current directory is called root. The system starts up with a directory inside root called sys. This contains system variables.

Commands

Taken directly from the core.rhlp help file.

NAME: add LIB: core USAGE: num1 num2 add DESC: Adds num1 and num2, and pushes the result onto the stack. NOTES: num1 and num2 have to be numbers.

NAME: sub LIB: core USAGE: num1 num2 sub DESC: Subtracts num1 and num2, and pushes the result onto the stack. NOTES: num1 and num2 have to be numbers.

NAME: mul LIB: core USAGE: num1 num2 mul DESC: Multiplies num1 and num2, and pushes the result onto the stack. NOTES: num1 and num2 have to be numbers.

NAME: div LIB: core USAGE: num1 num2 div DESC: Divides num1 and num2, and pushes the result onto the stack. NOTES: Num1 and num2 have to be numbers. Num2 cannot be zero.

NAME: disp LIB: core USAGE: item disp DESC: Takes the top item off of the stack and displays it.

NAME: peek LIB: core USAGE: item peek DESC: Like disp, but it does not pop the top element.

NAME: dup LIB: core USAGE: item dup DESC: Takes the top item off of the stack and pushes 2 copies of it.

NAME: drop LIB: core USAGE: item drop DESC: Takes the top item off the stack.

NAME: swap LIB: core USAGE: it1 it2 swap DESC: Swaps the top 2 items on the stack, so that 1 2 -} 2 1 .

NAME: rot LIB: core USAGE: i1 i2 i3 rot DESC: Takes the 3 top items on the stack and pushes them on in reverse order, so that 1 2 3 -} 3 2 1 .

NAME: clear LIB: core USAGE: clear DESC: Empties the entire stack.

NAME: cls LIB: core USAGE: cls DESC: Clears the screen.

NAME: dump LIB: core USAGE: dump DESC: Displays the contents of the stack.

NAME: mkdir LIB: core USAGE: name mkdir DESC: Creates a new directory called name. NOTES: Name must be a string. SAMEAS: prefix :

NAME: chdir LIB: core USAGE: name chdir DESC: Changes the current directory called name. NOTES: Name must be a string and either be a valid directory name or '..' . SAMEAS: prefix rb

NAME: isdir LIB: core USAGE: name isdir DESC: Pushes 1 if name is a directory, 0 otherwise. NOTES: Name must be a string.

NAME: del LIB: core USAGE: name del DESC: Deltes the item at name. SAMEAS: prefix ~

NAME: sto LIB: core USAGE: val name sto DESC: Stores val in the variable called name. NOTES: Name must be a string. SAMEAS: prefix =

NAME: rcl LIB: core USAGE: name rcl DESC: Recalls the varible in name to the stack. NOTES: Name must be a string and cannot be a directory name. SAMEAS: prefix $

NAME: list LIB: core USAGE: list DESC: Displays all the items in the current directory. SAMEAS: prefix @

NAME: dir LIB: core USAGE: dir DESC: Displays the current path.

NAME: exec LIB: core USAGE: code exec DESC: Executes code as RPOS batch. NOTES: Code must be a string.

NAME: eq LIB: core USAGE: i1 i2 eq DESC: Pushes 1 if i1 and i2 are equal, 0 otherwise.

NAME: ne LIB: core USAGE: i1 i2 ne DESC: Pushes 1 if i1 and i2 are not equal, 0 otherwise.

NAME: lt LIB: core USAGE: i1 i2 lt DESC: Pushes 1 if i1 is less than i2, 0 otherwise.

NAME: le LIB: core USAGE: i1 i2 le DESC: Pushes 1 if i1 is less than or equal to i2, 0 otherwise.

NAME: gt LIB: core USAGE: i1 i2 gt DESC: Pushes 1 if i1 is greater than i2, 0 otherwise.

NAME: ge LIB: core USAGE: i1 i2 ge DESC: Pushes 1 if i1 is grater than or equal to i2, 0 otherwise.

NAME: not LIB: core USAGE: bool not DESC: Pushes 0 if bool is 1, 0 otherwise.

NAME: and LIB: core USAGE: b1 b2 and DESC: Pushes 1 if b1 and b2 are 1, 0 otherwise.

NAME: or LIB: core USAGE: b1 b2 or DESC: Pushes 1 if b1 or b2 is 1, 0 otherwise.

NAME: doif LIB: core USAGE: bool code doif DESC: Executes code if bool is 1. NOTES: Code must be a string. SAMEAS: prefix ?

NAME: while LIB: core USAGE: cond code while DESC: Keeps executing code while the code in cond evaluates to 1. NOTES: Cond and code bust be strings.

NAME: rep LIB: core USAGE: num code rep DESC: Executes code num times and pushes the current iteration on the stack. NOTES: Num must be a number, and code must be a string.

NAME: repdir LIB: core USAGE: name code repdir DESC: For every item in the directory called name, pushes the item's name and executes code. NOTES: Name and code must be strings. Name must be a valid directory name, '.', or '..' .

NAME: size LIB: core USAGE: name size DESC: Pushes the number of items in the directory called name. NOTES: name must be a valid directory name, '.', or '..' . SAMEAS: prefix #

NAME: join LIB: core USAGE: s1 s2 join DESC: Joins s1 and s2 together, and pushes it on the stack.

NAME: move LIB: core USAGE: old new move DESC: Moves the directory called old into the directory called new. NOTES: old must be strings and must be a valid directory name. New may also be '..' .

NAME: copy LIB: core USAGE: old new copy DESC: Copies the directory called old into the directory called new. NOTES: old must be strings and must be a valid directory name. New may also be '..' .

NAME: lib LIB: core USAGE: name lib DESC: Imports the library called name. NOTES: Name must be a string and a valid library name. Libraries are in the enclosing filesystem and have the .rlib prefix. Libraries are written in Lua. SAMEAS: prefix *

NAME: libcmd LIB: core USAGE: list name libcmd DESC: Imports the commands in list from library called name. NOTES: Name must be a string and a valid library name. Libraries are in the enclosing filesystem and have the .rlib prefix. Libraries are written in Lua. List must be a space-seperated string.

NAME: func LIB: core USAGE: code name func DESC: Creates a user-defined command called name. When name is refrenced as a command later, code will be executed. NOTES: Code and name must be strings.

NAME: isvar LIB: core USAGE: name isvar DESC: Pushes 1 if name is a valid item, 0 otherwise. NOTES: Name must be a string.

NAME: isfunc LIB: core USAGE: name isfunc DESC: Pushes 1 if name is a valid command, 0 otherwise. NOTES: Name must be a string.

NAME: delfunc LIB: core USAGE: name delfunc DESC: Deletes the command called name. WARNING!!! This may cause grat damage to the system. Use this command wisely. NOTES: Name must be a string.

NAME: type LIB: core USAGE: item type DESC: Pushes 'number' if item is a number, 0 otherwise.

NAME: substr LIB: core USAGE: str start end substr DESC: Gets the substring of str, starting at start and ending and end. NOTES: start and end must be numbers. Str must be a string.

NAME: inp LIB: core USAGE: inp DESC: Gets a line of input and pushes it to the stack.

NAME: write LIB: core USAGE: write DESC: Gets input until CTRL+D is pressed on a newline, and then pushes it. SAMEAS: prefix }

NAME: root LIB: core USAGE: root DESC: Sets the current directory to root.

NAME: import LIB: core USAGE: name import DESC: Pushes the contents of outside file called name. NOTES: Files are in the outside filesystem and have the .rfil extenstion.

NAME: export LIB: core USAGE: val name export DESC: Set the contents of outside file called name to val. NOTES: Files are in the outside filesystem and have the .rfil extenstion.

NAME: save LIB: core USAGE: save DESC: Saves the system state to an outside file. NOTES: System Saves are in the outside filesystem and have the .rsav extenstion.

NAME: load LIB: core USAGE: load DESC: Loads the system state from an outside file. NOTES: System Saves are in the outside filesystem and have the .rsav extenstion.

NAME: call LIB: core USAGE: name call DESC: Executes the outside file called name in RPOS batch. NOTES: name must be a string. Files are in the outside filesystem and have the .rfil extenstion. SAMEAS: prefix %

NAME: run LIB: core USAGE: name run DESC: Executes the outside file called name as Lua code. NOTES: name must be a string. Files are in the outside filesystem and have the .rfil extenstion.

NAME: ren LIB: core USAGE: name newname ren DESC: Renames the item called name to newname. NOTES: Name and newname must be strings. Name must be a valid item name.

NAME: prompt LIB: core USAGE: opt prompt DESC: Configures the prompt based on opt. If opt is, it shows: 'S' - the size of the stack. 'T' - the top item on the stack. 'D' - The current path. 'C' - The current directorie's name.

NAME: help LIB: core USAGE: help DESC: Enters RPOS Interactive Help.

NAME: info LIB: core USAGE: info DESC: Displays the RPOS version information.

NAME: alias LIB: core USAGE: old new alias DESC: Aliases the command called old as new. NOTES: Old and new must be strings.

NAME: pshdir LIB: core USAGE: pshdir DESC: Pushes the current path on to the stack.

NAME: popdir LIB: core USAGE: dr popdir DESC: Sets the current path to dr. NOTES: dr has to be a string.

NAME: len LIB: core USAGE: str len DESC: Returns the lenght of str. NOTES: str has to be a string.

NAME: tos LIB: core USAGE: itm tos DESC: Converts itm to a string.

NAME: ton LIB: core USAGE: itm ton DESC: Converts itm to a number.

Prefixes

Again, taken from core.rhlp.

PREFIX: ' DESC: Builds a string. The characters after ' are pushed as a string.

PREFIX: " DESC: Builds a string. The characters after " are pushed as a string after replacing the occourenses of the sysvar srcchr with the sysvar repchr.

PREFIX: $ DESC: Recalls the referenced variable. NOTES: the referenced name must be a valid variable name.

PREFIX: = DESC: Pops a value off the stack ands sets the referenced variable to it.

PREFIX: : DESC: Creates the referenced name as a directory.

PREFIX: Right Brakcet DESC: Changes the current directory to the referenced directory. NOTES: The characters after must be a valid directory.

PREFIX: ~ DESC: Deletes the referenced item.

PREFIX: ? DESC: Does the referenced command if the top value on the stack is 1.

PREFIX: @ DESC: Displays the items in the referenced directory. NOTES: the referenced name must be a valid directory.

PREFIX: # DESC: Displays the number of items in the referenced directory. NOTES: the referenced name must be a valid directory.

PREFIX: & DESC: Displays the contents of the refrenced item.

PREFIX: % DESC: Calls the outside file refernced as RPOS batch code. NOTES: Files are in the enclosing filesystem and have the .rfil prefix.

PREFIX: * DESC: Imports the library refernced. NOTES: Libraries are in the enclosing filesystem and have the .rlib prefix. Libraries are written in Lua.

PREFIX: } DESC: Puts what you input until CTRL+D into the refernced variable.

PREFIX: + DESC: Adds to the refernced variable the sysvar inc. NOTES: the referenced name must be a number variable.

PREFIX: - DESC: Subtracts to the refernced variable the sysvar inc. NOTES: the referenced name must be a number variable.

System Varialbes

Also directly from core.rhlp.

NAME: errs TYPE: number DFALUT: 1 DESC: Set errs to 1 to display error messages, 0 otherwise.

NAME: disp TYPE: number DFALUT: 0 DESC: Set disp to 1 to display pushed items, 0 otherwise.

NAME: srcchr TYPE: string DFALUT: _ DESC: Used in the prefix " as the character to replace.

NAME: repchr TYPE: string DFALUT: DESC: Used in the prefix " as the character to replace with.

NAME: version TYPE: number DFALUT: -varies- DESC: The current version number.

NAME: bdate TYPE: string DFALUT: -varies- DESC: The current build date.

NAME: joinchr TYPE: string DFALUT: DESC: What to put in between the two arguments of the join command.

NAME: inc TYPE: number DFALUT: 1 DESC: What to increment and decrement variables by in the + and - prefixes.

NAME: pcf1 TYPE: string DFALUT: DESC: What to display before pcf2 in the prompt.

NAME: pcf2 TYPE: string DFALUT: S DESC: what the prompt displays. Don't set this sysvar directly, use the prompt command.

NAME: pcf3 TYPE: string DFALUT: rb DESC: What to display after pcf2 in the prompt.

NAME: errmsg TYPE: string DFALUT: DESC: The message of the last error that occoured.

NAME: pshloop TYPE: number DFALUT: 1 DESC: Set to 1 to push the counter in the commands rep and repdir, 0 otherwise.

NAME: term TYPE: number DFALUT: 0 DESC: Set to 1 to terminate on errors, 0 otherwise.

NAME: libs TYPE: directory DFALUT: -dir- DESC: Contains the names of the commands from all the imported libraries.

NAME: platform TYPE: string DFALUT: -varies- DESC: The platform of the RPOS shell currently running.

Implementation

A Lua implementation of RPOS is available here.