Mumble: A lisp in C

About

This is a Lisp written in C. It follows the outline in this Build Your Own Lisp book, though it then adds tweaks and quality of life improvements:

• A makefile
• Configurable verbosity levels
• Different and perhaps slightly more elegant printing functions
• A slightly different approach to evaluating functions
• Capturing Ctrl+D
• Float instead of ints

Conversely, it doesn't have:

• Function currying
• strings
• Variable arguments
• ...

Overall this might be mostly of interest as a pointer to the book that this is originally based on. And to readers of that same book, I'd be curious to see what you ended up with.

Installation and usage

Dependencies

This depends on editline, which can be installed on Debian/Ubuntu with:

git clone https://github.com/troglobit/editline
./autogen.sh
./configure
make all
sudo make install
ldconfig

Readers might also find it interesting to compile it with tiny c compiler rather than gcc, as it is significantly faster.

Compilation

git clone https://github.com/NunoSempere/mumble
make
# sudo make install # 

Usage

Simply call the ./mumble binary:

./mumble

Example usage

mumble> (1 2 3)
mumble> { 1 2 3 }
mumble> head {1 2 3}
mumble> { head {1 2 3) }
mumble> tail { 1 2 3 }
mumble> list ( 1 2 3 )
mumble> eval { head {1 2 3} } 
mumble> (eval { head {+ tail head } } ) 1 2 3 
mumble> len {1 2 3}
mumble> join { {1 2} {3 4} }
mumble> def {x} { 100 }
mumble> def {y} 100
mumble> (x y)
mumble> VERBOSITY=2
mumble> def {sq} (@ {x} {* x x})
mumble> sq 44
mumble> VERBOSITY=1
mumble> def {sqsum} (@ {x y} {(+ (sq x) (sq y))})
mumble> sqsum 2 3
mumble> VERBOSITY=0
mumble> def {init} (@ {xs} { list((head xs)) } )
mumble> def {kopf} (@ {xx} { head (list xx) } )
mumble> init {1 2}
mumble> kopf (1 2)
mumble> ifelse 1 2 3
mumble> if 1 2 3
mumble> ifelse 0 1 2 
mumble> if 0 1 2 
mumble> if {1 2 3} (1) (1)
mumble> def {positive} (@ {x} {> x 0})
mumble> def {fibtest} (@ {x} {if (> x 0) {+ x 1} 0 })
mumble> fibtest 2
mumble> def {fibonacci} (@ {x} {if (> x 1) { + (fibonacci (- x 2)) ( fibonacci ( - x 1 ) ) } 1} )
mumble> fibonacci 4
mumble> def {!} (@ {x} { if ( > 1 x) 1 { * x (! (- x 1)) } })
mumble> ! 100
mumble> def {++} (@ {x} { if ( > 1 x) 0 { + x (++ (- x 1)) } })
mumble> ++ 10
mumble>  def {++2} (@ {x} { / (* x (+ x 1)) 2 })
mumble> ++2 10

To do

• Define functions
• Define if, = and >
• Build fibonacci function
• Build factorial function

Gotchas

This doesn't currently run on Windows. But it easily could, with the preprocessor staments from parsing.c here.