https://github.com/dzangfan/basic-cc

YA compiler compiler in Racket
https://github.com/dzangfan/basic-cc

compiler racket yacc

Last synced: 5 days ago
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YA compiler compiler in Racket

• Host: GitHub
• URL: https://github.com/dzangfan/basic-cc
• Owner: dzangfan
• License: gpl-3.0
• Created: 2023-08-05T06:59:40.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-08-19T12:31:25.000Z (about 1 year ago)
• Last Synced: 2023-08-19T13:43:20.727Z (about 1 year ago)
• Topics: compiler, racket, yacc
• Language: Racket
• Homepage:
• Size: 53.7 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.org
  • License: LICENSE

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README

        
* basic-cc -- An academic compiler compiler

This repo contains a series of tools for building compilers, including lexer, parser (LL, LR(0), LR(1)), and debugger. This library aims to keep the complexity at a low level and provide intuitive interfaces, meaning that it is quite theoretical rather than practical.

#+begin_src racket

  #lang racket

  (require basic-cc/language)

  (define-language s-exp

    "\\s+"                                ; Ignore characters matching this pattern

    (L "\\(") (R "\\)") (SYM "\\w+")      ; Name of token must be [A-Z]+

    (form SYM (L items R) (L R))          ; form -> SYM | L items R | L R

    (items form (items form)))

  (define source "(flatten (() (1 (2))))")

  (s-exp-cut source)

  ;; #(# # # # #

  ;;   # # # # #

  ;;   # # # #)

  (s-exp-read source)

  ;; (form #

  ;;       (items

  ;;        (items (form #))

  ;;        (form #

  ;;              (items

  ;;               (items (form # #))

  ;;               (form #

  ;;                     (items (items (form #))

  ;;                            (form #

  ;;                                  (items (form #))

  ;;                                  #))

  ;;                     #))

  ;;              #))

  ;;       #)

#+end_src

The macro ~define-language~ will define a set of variables and functions to accomplish syntactic parsing. As shown above, ~s-exp-cut~ and ~s-exp-read~ play important roles in this process. Both of them have the same signature:

#+begin_src racket

  (language-cut/read in #:file filename)

#+end_src

where ~in~ is either a ~input-port~ or a string and ~filename~ is a string pointing to source of the input as metadata. Besides, ~define-language~ defines the following variables, though you can ignore them completely.

- ~s-exp/lexicon~ Internal lexer object

- ~s-exp/grammar~ Classical context-free grammar defined by 4-tuple

- ~s-exp/automaton~ LR(1) automaton derived from ~s-exp/grammar~

- ~s-exp/table~ General LR table for syntax parsing

- ~s-exp/language~ 4-tuple of variables above

Three options are provided for further control:

- ~(#:enable-EOL)~ Generate EOL token for newline (default not)

- ~(#:allow-conflict)~ Prevent the compiler compiler from raising exception when syntactic conflicts are found

- ~(#:driver driver)~ Specify the parsing method, where driver is ~LR.0~ or ~LR.1~

A bigger example can be found [[https://github.com/dzangfan/juhz/blob/79af5d2ba7a417e5000e144fd8944519f537d6e4/language.rkt][here]].