What are we doing here?

The purpose of this program is to determine whether a given string of characters is a 'Well Formed Formula' in a propositional logic sense. More information about well formed formulas can be found here

What symbols can I use, and how do I put them in the box?

The following is a list of characters that can be used

• ✰ Any alphabetical character from A all the way to Z
• ✰ The conditional operator ( → ) can be inserted if you press the shift key and the > key at the same time
• ✰ The bi-conditional operator ( ↔ ) can be inserted if you press the shift key and the < key at the same time
• ✰ The disjunction operator ( ∨ ) can be inserted if you press the shift key and the v key at the same time
• ✰ The conjunction operator ( & ) can be inserted as you normally would type an ampersand
• ✰ The negation operator ( - ) can be inserted as you normally would type a dash
• ✰ Opening ( and closing ) parentheses can be inserted as you normally would type them
• ✰ Spaces!

The following list, though not exhaustive, cannot be put in the box

• ☹ Numerals ie 1234567890
• ☹ Punctuation like , . or even ?
• ☹ Brackets like { or [
• ☹ Your mother's name
• ☹ Probably some other stuff

Sometimes when my formula is not well formed the error message is not very helpful

I'm sorry about that. When a forumla is not well formed, it becomes very hard to parse correctly and sometimes the error messages don't make a whole lot of sense. Other times, however, you will get a meaningful error message so be thankful then.

I found a formula that I think is well formed but this program doesn't think so, or vice versa.

Awesome! You broke everything! Please let me know by using the contact form