This is an extensive list of all the built-in functions EPL has to offer.
Input can be handled with Read a %type% into %reference%, which reads a value from standard input and stores it at the given address. Values can also be fetched directly without storing with a %type% read from input. Note that in both cases the type has to be specified, and it must be either string or a primitive.
For output, there are three variations of print:
| Operation | Procedure |
|---|---|
| Printing a value to standard output | Print %value% |
| Printing a value followed by an end of line | Print %value% in a line |
| Printing an empty line | Print an empty line |
The string representation of any value can be obtained with %value% as a string.
A reference to an aribtrary element of a list can be obtained by using the element of %list% at %int%. As with all other references, once it's stored it becomes a value, so the original value in the list can no longer be modified. However, it can be modified during the call in which it's obtained. For example:
Add 5 to the element of L at 3.
The function Swap %reference% with %reference% allows swapping the values at the two given addresses between each other. Both references must point to values of the same type.
A single reference can be modified as well using Set %reference% to %value%. The given value and the one pointed at by the reference must have the same type.
Most operations on numbers have two variations: one in the form of an operator that returns the resulting value, and one in the form of a procedure that applies the operation to an existing reference:
| Operation | Operator | Procedure |
|---|---|---|
| Addition | %number% plus %number% |
Add %number% to %reference% |
| Subtraction | %number% minus %number% |
Subtract %number% from %reference% |
| Multiplication | %number% times %number% %number% multiplied by %number% |
Multiply %reference% by %number% |
| Division | %number% divided by %number% |
Divide %reference% by %number% |
| Whole division | the quotient of %whole number% and %whole number% |
Quotient %reference% by %whole number% |
| Exponentiation | %number% raised to the power of %number% |
Raise %reference% to the power of %number% |
| Rounding | %number% rounded |
Round %reference% |
| Ceiling | the ceiling of %number% |
Round %reference% up |
| Floor | the floor of %number% |
Round %reference% down |
| Truncating | %number% truncated |
Truncate %reference% |
A few more complex ones are only available as operators, since they don't really work as a verb:
| Operation | Operator |
|---|---|
| Logarithm | the logarithm of %number% to base %number% |
| Module | %whole number% module %whole number% the remainder of dividing %whole number% by %whole number% |
| Root | the square root of %number% |
| Absolute value | the absolute value of %number% |
Equality can be tested for using %value% is equal to %value% and %value% is not equal to %value%, where the two arguments are any two values of the same type. They both perform a deep comparison.
Numbers can also be compared using operators >, >=, <, and <=, which are called greater than, greater than or equal to, less than, and less than or equal to respectively.
There are three queries about the size of a list:
| Operation | Operator |
|---|---|
| Check if empty | %list% is empty |
| Check if not empty | %list% is not empty |
| Get length | the length of %list% |
There are queries about the presence of a value as well:
| Operation | Operator |
|---|---|
| Check if element is in list | %list% contains %value% |
| Get index of element | the index of %value% in %list% |
Lists can also be modified. Operators return deep copies, and procedures modify the original lists passed by reference.
Adding items:
| Operation | Operator | Procedure |
|---|---|---|
| Push item at beggining | %list% with %value% added at the beggining |
Add %value% at the beggining of %reference% |
| Push item at end | %list% with %value% added at the end |
Add %value% at the end of %reference% |
| Insert item at position | %list% with %value% added at %whole number% |
Add %value% to %reference% at %whole number% |
Removing items:
| Operation | Operator | Procedure |
|---|---|---|
| Remove nth element | %list% without the element at %whole number% |
Remove the element at %whole number% from %reference% |
| Remove first apparition of element | %list% without the first apparition of %value% |
Remove the first apparition of %value% from %reference% |
| Remove all apparitions of element | %list without all apparitions of %value% |
Remove all apparitions of %value% from %reference% |
| Tail | %list% without its first element |
Remove the first element from %reference% |
| Init | %list% without its last element |
Remove the last element from %reference% |
| Take from beggining | the first %whole number% elements in %list% |
Leave the first %whole number% elements in %reference |
| Take from end | the last %whole number% elements in %list% |
Leave the last %whole number% elements in %reference |
| Drop from beggining | %list% without its first %whole number% elements |
Remove the first %whole number% elements from %reference% |
| Drop from end | %list% without its last %whole number% elements |
Remove the last %whole number% elements from %reference% |
Lists can also be modified according to other lists:
| Operation | Operator | Procedure |
|---|---|---|
| Append | %list% appended to %list% |
Append %list% to %reference% |
| Prepend | %list% prepended to %list% |
Prepend %list% to %reference% |
| Remove items in common | %list% without the elements in %list% |
Remove the elements in %list% from %reference% |
A list can be emptied out by using Empty out %reference%.
A list with the numbers in an interval can be generated by using the list from %whole number% to %whole number%.
| Operation | Operator | Procedure |
|---|---|---|
| To uppercase | %char% in uppercase |
Transform %reference% to uppercase |
| To lowercase | %char% in lowercase |
Transform %reference% to lowercase |
All basic boolean operations are available:
| Operation | Operator |
|---|---|
| AND | %bool% and %bool% |
| OR | %bool% or %bool% |
| XOR | %bool% or %bool% but not both |
| NOT | not %bool% %bool% negated |
A reference to a boolean can be negated using negate %reference%.
There are a few other operations: %bool% is true, %bool% is false, and whether %boolean%. They don't make too much sense on their own, but allow writing more natural sentences such as:
Let X be whether N is larger than N.
If X is true:
...