112 lines
2.4 KiB
Markdown
112 lines
2.4 KiB
Markdown
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# Reference
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The following is an informal overview of FSKalc's capabilties.
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## Expressions
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### Number literal
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Example:
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```
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8.5
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```
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### Variable read
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Example:
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```
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a
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```
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Will print an error message if variable is undefined. The `ans` variable implicitly refers to the result of the last expression statement.
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### Parentheses for precedence
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Example:
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```
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(5+6)*7
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```
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Parentheses increase precedence.
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### Parentheses for function calls
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Parentheses can also represent function calls, if they contain more than one element (separated by a space).
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Example:
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```
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(sin 50)
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```
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### Arithmetic operators
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The following operators are valid, in decreasing precedence:
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- `^` power; right associative
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- `-` unary negation; note that multiple negations next to eachother are invalid!
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- factor precedence:
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- `*` multiplication; left associative
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- `/` division; left associative
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- `//` integer (flooring) division; left associative
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- `%` modulo; left associative
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- term precedence:
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- `+` addition; left associative
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- `-` subtraction; left associative
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## Statements
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Statements are the top level construct. Every line in an FSKalc program has to be a statement.
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### Expression statement
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Any valid expression is also a valid statement. The result of expression statements is printed to the screen, and also assigned to the variable names `ans`.
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### Variable assignments
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Variable assignments have the following syntax:
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```
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identifier = expression
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```
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Where the identifier is a string of characters containing only letters and underscores.
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Existing variables or functions can be overwritten by new variables/functions.
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### Function declaration
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Function declaration has the following syntax, demonstrated by an example below.
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```
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double x = x * 2
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```
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Warning! as there are no scopes in FSKalc, passing
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arguments to functions will modify the global scope.
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## Builtins
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### Builtin Constants
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- pi
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- tau (pi * 2)
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- e (euler's number)
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- inf (infinity)
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- nan (not a number)
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### Builtin Functions
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- sin, cos, tan - they take 1 argument, in radians
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- arcsin, arccos, arctan - they take 1 argument, they return in radians
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- sqrt - returns square root, optional second argument is the power, default of 2
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- log - logarithm, optional second argument is the base, default of 10
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- ln - natural logarithm
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- exp - returns e to the power of the argument
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## Comments
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Comments can be inside matching `(*`, `*)` parentheses.
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