DSL语法解析器生成器：dropincc.java
jopen
11年前
dropincc.java 是
- 一个简单、好用的语法解析器生成器；
- 专为java语言环境下，实施DSL方案而设计；
- 特点：使用纯java语法(Fluent Interface)制定用户的词法、语法规则；jdk1.6 compiler API动态编译为字节码；自动管理字节码、用户无需关心具体生成的解析器源码；专为DSL打造，相对与使用其它常见工具(javacc, antlr等)做DSL解析，代码量急剧下降；上手较为容易，让用户更加关注自身业务内容
- 需要jdk1.6或以上版本运行,无任何其它依赖
- 识别LL(*)语法
/** * EBNF of Calculator: * <pre> * calc ::= expr $ * expr ::= addend (('+'|'-') addend)* * addend ::= factor (('*'|'/') factor)* * factor ::= '(' expr ')' * | '\\d+(\\.\\d+)?' * </pre> */ public static void main(String... args) throws Throwable { Lang c = new Lang("Calculator"); Grule expr = c.newGrule(); c.defineGrule(expr, CC.EOF).action(new Action() { public Double act(Object matched) { return (Double) ((Object[]) matched)[0]; } }); TokenDef a = c.newToken("\\+"); Grule addend = c.newGrule(); expr.define(addend, CC.ks(a.or("\\-"), addend)).action(new Action() { public Double act(Object matched) { Object[] ms = (Object[]) matched; Double a0 = (Double) ms[0]; Object[] aPairs = (Object[]) ms[1]; for (Object p : aPairs) { String op = (String) ((Object[]) p)[0]; Double a = (Double) ((Object[]) p)[1]; if ("+".equals(op)) { a0 += a; } else { a0 -= a; } } return a0; } }); TokenDef m = c.newToken("\\*"); Grule factor = c.newGrule(); addend.define(factor, CC.ks(m.or("/"), factor)).action(new Action() { public Double act(Object matched) { Object[] ms = (Object[]) matched; Double f0 = (Double) ms[0]; Object[] fPairs = (Object[]) ms[1]; for (Object p : fPairs) { String op = (String) ((Object[]) p)[0]; Double f = (Double) ((Object[]) p)[1]; if ("*".equals(op)) { f0 *= f; } else { f0 /= f; } } return f0; } }); factor.define("\\(", expr, "\\)").action(new Action() { public Double act(Object matched) { return (Double) ((Object[]) matched)[1]; } }).alt("\\d+(\\.\\d+)?").action(new Action() { public Double act(Object matched) { return Double.parseDouble((String) matched); } }); Exe exe = c.compile(); System.out.println(exe.eval("1 +2+3+(4 +5*6*7*(64/8/2/(2/1 )/1)*8 +9 )+ 10")); }