Special Variables

Variables are typed.

They can be a primitive like int or str. They can also be a structured document like json, csv or sexpr.

Variables can also have a string representation, for compatibility with older POSIX idioms, as well as a native object format.

Glossary Of Terms

To help better understand how variables work under the hood, blow is a glossary of terms:

• primitive: this refers to the atomic component of a data-type. In other words, the smallest possible format for a piece of data. Where a JSON file might arrays and maps, the values for those objects cannot be divided any smaller than numbers, strings or a small number of constants like true, false, and null.

• scope: this is how far outside the code block that a particular variable can be written to, or read from.

• local (scope): this refers to variables that cannot be read nor modified outside of the current function. Thus one function cannot read nor write to a variable in another function.

• module (scope): these variables are accessible by any function or routine from within the same module. You'll only need module scoped variables if you're writing modules -- and even then, only if you want that variable available to all functions within that module.

• global (scope): these are variables which are accessible from any function, anywhere within Murex.

• environmental variables: sometimes written as env vars for short, these are system variables. They can be passed from one process to another, so careful what secrets you store and what software you run while you have sensitive env vars defined.

• reserved variables: this refers to variables that are read only. Some reserved variables are dynamic and thus can change their value depending on contextual circumstances.

Pages

• Numeric (str): Variables who's name is a positive integer, eg 0, 1, 2, 3 and above
• $., Meta Values (json): State information for iteration blocks
• ARGV (json): Array of the command name and parameters within a given scope
• COLUMNS (int): Character width of terminal
• EVENT_RETURN (json): Return values for events
• HOME (path): Return the home directory for the current session user
• HOSTNAME (str): Hostname of the current machine
• LINES (int): Character height of terminal
• LOGNAME (str): Username for the current session (historic)
• MUREX_ARGV (json): Array of the command name and parameters passed to the current shell
• MUREX_EXE (path): Absolute path to running shell
• OLDPWD (path): Return the home directory for the current session user
• PARAMS (json): Array of the parameters within a given scope
• PWDHIST (json): History of each change to the sessions working directory
• PWD (path): Current working directory
• RANDOM (int): Return a random 32-bit integer (historical)
• SELF (json): Meta information about the running scope.
• SHELL (str): Path of current shell
• TMPDIR (path): Return the temporary directory
• USER (str): Username for the current session