donydchen/dragon-front

The comment for A Complete Front End of the dragon book.

Dragon-Front

THE COMMENT FOR A COMPLETE FRONT END OF THE DRAGON BOOK
2015 SYSU COMPILER PROJECT 4

##文件结构简介

• bin: 由eclipse自动生成的可执行文件
• doc: javadoc生成的注解文档，使用命令：javadoc inter/*.java lexer/*.java main/*.java parser/*.java symbols/*.java -d ../doc -encoding UTF-8 -charset UTF-8
• ref: 其中CompilerAppendixA.pdf是龙书附录A，而documents.pdf则是编译器源码的分析与注解
• src: 完整编译器前端的源码，含注释
• uml: 编译器前端类的类图，包含jpg档和uxf档，其中uxf档请使用UMLet打开

##编译器识别语言的文法

program -> block
block -> { decls stmts }
decls -> decl decls | epsilon
decl -> type id
type -> basic dims
dims -> [ num ] dims | epsilon
stmts -> stmt stmts | epsilon

stmt -> ;
      | if ( bool ) stmt 
      | if ( bool ) stmt else stmt
      | while ( bool ) stmt
      | do stmt while ( bool ) ;
      | break ;
      | block
      | assign
assign -> id offset = bool ;
offset -> [ bool ] offset | epsilon

bool -> join | join || bool
join -> equality | equality && join
equality -> rel | rel == equality | rel != equality
rel -> expr 
     | expr < expr | expr <= expr 
     | expr >= expr | expr > expr
expr -> term | term + expr | term - expr
term -> unary | unary * term | unary / term
unary -> - unary | ! unary | factor
factor -> ( bool ) | num | real | true | false | id offset

dragon-front's Issues

error: /usr/ccs/bin/yacc -v doc/front.y

Hi Donald,

I dont find the front.y file in your folder. Could you explain what does this command do?

Good work!