Following a specific io syntax

[8hantanu]

To do:

• Set a fixed syntax so there is no ambiguity while giving input.
• Update the wiki by adding a page for input syntax and rules under User Manual section.
• Output string (from the tokensToString() method) must also follow this syntax as it can be used again in an input.
• Changes must be made in io/tokenize.py and io/checks.py accordingly.

Some examples:

• Giving input as sin x is not allowed. The operand must always be contained in brackets like sin(x).
• Should x^2y be interpretted as (x^2)*y or x^(2y) ?
• Coefficient must be given before variables i.e 2xy is accepted xy2 is not.
• Also use * when multiplying with expressions i.e. 2*(x+y) and (x+y)*(x-y) instead of 2(x+y) and (x+y)(x-y).
• Always use a number before decimal point. Use 0.1 instead of .1 #113

You can list any examples of ambiguous inputs(or any changes if required to the current syntax) in the comments below.
Note: Some of the above examples might not have been implemented yet. Any examples can be suggested which might be helpful when implementing them in future.

[Alii-Khaled]

These are Input forms I think VisMa should have.

- Spaces inside the input Expression are allowed but any space between the Trigonometric, Logarithmic, Exponential & hyperbolic functions are not allowed ( like: Si n(x) ).

- Any Trigonometric, Logarithmic, Exponential & hyperbolic functions must have at least 1 closing & 1 opening Bracket which contain the function's expression like: sin(x+4)

- Any Power must have at least a variable or a constant, and if it has more than one, it should be put between 2 Brackets. like: e^x ... e^(x+3) and should use ( ^ ) not ( ** ).

- Upper and lower cases are allowed.

- Constants or Variables which are positive shouldn't have ( + ) prefix for them, while negative should have a prefix ( - ) sign like: +X is not allowed.

- 1X or -1X will be directly changed into X & -X respectively.

- Equal sign should have at least one variable or constant on each side of it.

Whenever I found any other ambiguous input syntax I will add it in here.