Method parse

chapter22/src/main/java/com/seaofnodes/simple/Parser.java:134–186

()

    private <N extends Node> N ctrl(N n) { return _scope.ctrl(n); }

    public void parse() {

        _scope.define(ScopeNode.CTRL, Type.CONTROL   , false, null, _lexer);
        _scope.define(ScopeNode.MEM0, TypeMem.BOT    , false, null, _lexer);
        _scope.define(ScopeNode.ARG0, TypeInteger.BOT, false, null, _lexer);

        ctrl(XCTRL);
        _scope.mem(new MemMergeNode(false));

        // Parse the sys import
        _lexer = new Lexer(com.seaofnodes.simple.sys.SYS);
        while( !_lexer.isEOF() ) {
            parseStatement();
            _lexer.skipWhiteSpace();
        }

        // Reset lexer for program text
        _lexer = new Lexer(_code._src);
        _xScopes.push(_scope);

        // Parse whole program, as-if function header "{ int arg -> body }"
        parseFunctionBody(_code._main,loc(),"arg");

        // Kill an empty default main.  Keep only if it was explicitly defined
        // (programmer asked for a "main") or it has stuff (i.e. beginner
        // default main).
        FunNode main = _code.link(_code._main);
        StopNode stop = _code._stop;
        if( main.ret().expr()._type==Type.TOP && main.uctrl()==null ) {
            // Kill an empty default main; so it does not attempt to put a
            // "main" in any final ELF file
            main.setDef(1,XCTRL); // Delete default start input
            stop.delDef(stop._inputs.find(main.ret()));
        } else {
            // We have a non-empty default main.
            // Check for an explicit main
            for( Node n : stop._inputs )
                if( n instanceof FunNode fun && fun._name.equals("main") )
                    // Found an explicit "main" AND we have a default "main"
                    throw error("Cannot define both an explicit main and a default main");
            main._name = "main";
        }

        if( !_lexer.isEOF() ) throw _errorSyntax("unexpected");

        // Clean up and reset
        _xScopes.pop();
        _scope.kill();
        for( StructNode init : INITS.values() )
            init.unkeep().kill();
        INITS.clear();
        stop.peephole();
    }

    /**
     *  Parses a function body, assuming the header is parsed.