deepakjois / hs-logo Goto Github PK

pr 3 * (5 + 2) / 4
pr 3 * 7 / 4
pr 3 * 7 + 4

yields

21.0
21.0
25.0

• Add a little bit of padding
• Use an appropriate stroke width
• Use a white background and a black foreground

• Enumerate all common errors
• Find a way to robustly handle each of those error cases
• Keep track of all line numbers, and make error messages indicate the most accurate line number

• Fix hs-logo.cabal
• Compile without warnings
• Haddock comments

Currently use an evaluator which sits on top of ParsecT to do the heavy liftting of reading input. This task is to change the evaluator to avoid that.

• Also include parsing unary minus before expressions

Can't install because of this, I will try checking out the github project and installing that. Is there a release planned?

Currently, the Logo interpreter calls the SVG backend via the helper method defaultMain, passing the arguments using withArgs.

This can be made better if we directly call the SVG backend, using something like the renderDia method.

Here are some examples that will be good to be able to draw in hs-logo

• http://u2d.com/turtle_js/index.html
• http://www.mathcats.com/gallery/15wordcontest.html

repeat 4000 [repeat 34 [fd 12 rt 10] rt 90]

causes stack overflow.

for [l 1 10 1] is invalid, whereas for [ l 1 10 1 ] is valid.

http://www.cs.berkeley.edu/~bh/v2ch14/manual.html

• while
• if
• for
• dotimes

repeat 5100 [fd 10 rt arctan (remainder repcount 100) / 100]

Produces some bizarre output, which does not match the one at the Logo 15-word challenge page at all.

Looks at the make_os_package.sh script in the pandoc project.

A great reason to do this is to allow people to install hs-logo without needing to install Haskell. Hopefully, when we have a cleaner and more robust implementation and user guide, people would want to use it without compiling it from source.

Currently there are only types corresponding to Logo tokens. We also need a result type that will represent the outcome of evaluating an expression or result.

Clean up some bad choice of var names in code, that were chosen in the interest of expediency.

This should be as simple as adding a map in LogoContext

Currently the evaluation logic in Evaluator.hs is pretty awkward. This makes implementing control primitives like for a bit cumbersome. Here are some of the problems:

• eval method works only on binary expressions with NumLiteral tokens on both sides
• evaluating a list involves calling a different method called evaluateList

Here are some initial ideas to fix this:

• Rename eval to evalBinOp or something
• Have methods for each type of operation, like evalWord, evalExpr, evalList
• Have a new method called eval which does pattern matching to determine what kind of evaluation to perform on a token, and then return a logotoken as a return type.
• Change the control structures to use eval so that they dont have to be concerned about what is passed in

Need to take a list of raw LogoToken types and evaluate them to return a LogoToken which is one of the Logo data types: word, number or list.

• Hakyll code needs to be tweaked
• Page code needs to be updated

WIth inspiration from diagrams-contrib