Build your own LISP

Exercises and programs based on this tutorial.

Changelog

Update 1

Added program prompt.c

• Added a simple user prompt
• Released lispy v0.0.1!

Update 2

Updated prompt.c and Makefile

• Support for readline and command history.
• Proper error handling of input
• No limit on size of input
• Linked readline library
• Update Makefile
• Released lispy v0.0.2!

Update 3

• Fixed typo
• Define TRUE/FALSE in prompt.c

Update 4

• Added mpc as submodule

Update 5

• Symlinked mpc.h and mpc.c
• Solved some exercises of Chapter 06 at exercises.md
• Created Parsers for 'Reverse Polish notation' and defined language using Regex
• Modified prompt to echo ast on correct syntax or, display error
• Cleanup mpc parsers at exit
• Released lispy v0.0.3!

Update 6

• Added modulo(symbol %) in list of operators
• Realized parsers doesn't handle bad input (eg: Bad number of operands)

Update 7

• Added .clang-format
• Formatted prompt.c

Update 8

• Updated .clang-format
• Added .gitignore
• Initial support for evaluating expressions

Update 9

• Added some comments
• Renamed some functions
• Refactor if-else

Update 10

• Removed debug print statments
• Released lispy v0.0.4!

Update 11

• Removed unnecessary function to calculate total number of nodes

Update 12

• Move evaluation of ast to seperate header
• Add some documentation
• Updated Makefile to include eval

Update 13

Created lval.h and lval.c

• Store numbers and errors as LVal's (Lispy values)
• Create methods to operate on LVal's
• Modify eval and calc functions to accept and return LVal's
• Add some kind of error handling using enums
• Note: LERR_BAD_OP is handled by parser...
• Modified Makefile to include lval.c
• Removed unnecessary includes from files

Update 14

• Disabled evaluation for refactoring
• Removed a lot of memory leaks present from Day 1
• LVal struct now holds more fields
• Error are now strings
• A lot of dead code present
• Program compiles and gives correct output

Update 15

• Document public/private functions in lval.c
• Evaluate expressions
• Print result of expression rather than expression itself
• Released lispy v0.0.5!

Update 16

• Added support for Quoted(Q)-Expressions
  • In lang ({})
  • In LVal types
• Use macros for simplifying code (LASSERT)
• Refactor code for DRY
• Added logic for handling qexpr
• Derived sexpr functions for use with qexpr
• Added operator for qexpr like head, tail, etc.

Update 17

• Updated prompt to display lispy version v0.0.5
• Added documentation
• Divided source file using comments

Update 18

• Released lispy v0.0.6!

Update 19

• Forward declare structs LVal, LEnv along with their typedef's
• Forward declare function pointer LBuiltin
• Update LVal struct to include LBuiltin
• Declare all public functions of lval.h inside lval.c
• Remove dead code inside lval.h
• Restructure lval.c
• Added comments in lval.c
• Updated prompt.c and Makefile to use libedit instead of readline
• Also added a newline character to exit message
• Commit to make shorter discriptive commits!

Update 20

• Define LEnv struct
• Modify lval_wrap_err to parse variable arguments as error string
• Add LVal wrapper for LBuiltin's
• Add function to print type of LVal
• Add logic to handle LBuiltins in lval_del, lval_print
• Add a function to deep copy LVal's
• Commented some functions
• More re-ordering and restructuring of files

Update 21

• Declare and define functions to operate on LEnv's
• Finally have an idea of how lenv_get works
  • i.e the lval passed is itself a symbol instead of a value

Update 22

• Updated LASSERT to be variadic
• Added other assertions
• Added some documentation on the macros
• Breaks previous LASSERT's

Update 23

• Fix LASSERT_NOT_EMPTY to check for children of child of LVal instead, of child itself
• Update various builtins signature to pass LEnv's
• Rename LASSERT_* to LASSERT_CHILD_* for explicitness
• Accidentally replaced all a's with lval in comments..
  • Similarly with e and lenv
  • Resolved using my superb REGEX skills and determination!
• Also made some corrections along the way to comments
• For some weird reason I find An LVal, An LEnv more natural than using A ...
• Builtins like list, head, tail, eval, etc. now also require passing an LEnv
  • Passed an LEnv even when not required,
  • which led to -Wunused-parameter which was resolved adding a void statment
• Added modulo operator logic in builtin_op which to my suprise was missing!
• Added methods to declare and intialize builtin's inside LEnv's

Update 24

• Update signature and definition of lval_eval* to accept LEnv for getting symbols
• Also updated their documentation
• Improved error-handling in lval_eval_sexpr
• Fixed lval_eval signature in builtin_eval (which should have been fixed already in earlier commits...)

Update 25

• Update documentation for lval_eval from previous commit
• Made some LEnv related functions public for prompt.c
• Created a global LEnv for storing session symbols in prompt.c
• Updated sym regex
• Still need to debug some memory managment issues but somewhat complete
  • Like dumps core on passing wrong number of arguments to def
  • Reachable blocks are still present even after moving from readline to libedit

Update 26

• Turns out: > - Like dumps core on passing wrong number of arguments to def
  • Dumps core for every builtin
• Fixed the above described bug by removing typo s/sizeof(MAX_ERR)/MAX_ERR
• Fixed some error string formatting
• Add modulo to list of symbols
• Still a bit hazy how LBuiltin's work as a whole..
• Released lispy v0.0.7!

Update 27

• Modify LVal struct to have additional fields related to LBuiltin's
• s/fun/lbuiltin

Update 28

• Added wrapper function for lambda expressions
• Fixed a typo
• Added cases for LVAL_FUN to handle builtins and user-defined lambda expressions
• Code does not compile due to lenv_copy not defined

Update 29

• Builtin for lambda expressions
• Added builtin to lenv_add_builtin
• Still does not compile, due to previous error.

Update 30

• Added field parent inside LEnv struct
• Updated lenv_new to also intialize parent
• Updated lenv_get to check for local and global environment for variables
• Implemented lenv_copy to copy environments
• Implemented lenv_put_global to add variable directly to parent environment rather than local.
• Typecast lenv to void in builtin_lambda
• Won't compile Segfaults (hopefully) due to unimplemented builtins..

Update 31

• Modified builtin_def to builtin_var for handling cases of different environment

Update 32

• Updated macro comments
• Seperate cases for LVAL_NUM and LVAL_FUN in lval_del
• Fix bug in lval_copy
• Implement lval_call
• Invoke lval_call instead of lbuiltin in lval_eval_sexpr
• Fixed whitespace
• Added/Modified comments
• Replace lval_wrap_str with lval_wrap_sym
• Removed stupid allocation bug in lval_copy! Code runs!

Update 33

• Replaced Commit messages in this readme with updates..
• Changed first to lfun in lval_eval_sexpr which I find more fitting..
• Grouped builtins in lenv_init_builtins
• Removed unnecessary level of indentation inside quotes

Update 34

• Added code to handle variable number of arguments
• Fixed some comments/variables
• Realized builtin_sub is broken!

Update 35

• Added some comments
• Released lispy v0.0.8!

Update 36

• Added builtins for conditionals
• Added declaration of a couple of functions and descriptive comments
• Added if builtin
• Added a missing \n
• Moved some code within the file

Update 37

• Released lispy v0.0.9!

Update 38

• Support for strings
• Updated corresponding functions/parser syntax
• Added support functions for printing/reading strings
• Added related documentation
• Also some code movement
• Added support for comments

Update 39

• Parsers are now declared in parsers.h for sharing globals
• Added support for loading files using mpc_parse_contents
• Added support for printing strings
• Added support for creating errors from strings
• Added more functions required by prompt.c to lval.h
• Added support for running files using command-line arguments
• Released lispy v0.0.10!