error.cpp

由一个古老的BASIC解释器改进而成, 保留了ANSI C固有的艺术美感.

// error.cpp

#include "error.h"

#include <sstream>
#include <algorithm>

namespace {

struct errcode {
	const BlErrNo err;
	const char * const str;
	errcode (BlErrNo nerr, const char * nstr) :
		err (nerr),
		str (nstr)
	{ }
};

// Can't declare const or Borland can't expand find_if. Why?
errcode table []= {
	errcode (ErrNoError,            "No error"),
	errcode (ErrSyntax,             "Syntax horror"),
	errcode (ErrMismatch,           "Type mismatch"),
	errcode (ErrGosubWithoutReturn, "GOSUB without RETURN"),
	errcode (ErrReturnWithoutGosub, "RETURN without GOSUB"),
	errcode (ErrNextWithoutFor,     "NEXT without FOR"),
	errcode (ErrNotImplemented,     "Not implemented"),
	errcode (ErrDivZero,            "Division by zero"),
	errcode (ErrDataExhausted,      "Data exhausted"),
	errcode (ErrInvalidCommand,     "Invalid command"),
	errcode (ErrPolite,             "Programmer is too polite"),
        errcode (ErrBadSubscript,       "Bad Subscript"),
        errcode (ErrOutMemory,          "Out of memory"),
        errcode (ErrAlreadyDim,         "Array already dimensioned"),
        errcode (ErrNoContinue,         "Cannot CONTinue"),
        errcode (ErrFileNumber,         "Bad file number"),
        errcode (ErrFileMode,           "Bad file mode"),
        errcode (ErrFileAlreadyOpen,    "File already open"),
	errcode (ErrFileRead,           "Error reading file"),
        errcode (ErrFileWrite,          "Error writing file"),
	errcode (ErrUntilWithoutRepeat, "UNTIL without REPEAT"),
        errcode (ErrWendWithoutWhile,   "WEND without WHILE"),
        errcode (ErrWhileWithoutWend,   "WHILE without WEND"),
        errcode (ErrBlassicInternal,    "Internal Blassic error"),
        errcode (ErrNoDynamicLibrary,   "Dynamic library not found"),
        errcode (ErrNoDynamicSymbol,    "Symbol not found in dynamic library"),
        errcode (ErrCannotResume,       "Cannot RESUME"),
	errcode (ErrNoLabel,            "Label does not exist"),
	errcode (ErrMisplacedLocal,     "LOCAL out of subroutine"),
        errcode (ErrFieldOverflow,      "FIELD overflow"),
	errcode (ErrFileNotFound,       "File not found"),
	errcode (ErrLineExhausted,      "Line numbers exhausted"),
        errcode (ErrFunctionNoDefined,  "User function undefined"),
	errcode (ErrIncompleteDef,      "User function incomplete"),
	errcode (ErrInvalidDirect,      "Invalid direct command"),
        errcode (ErrBadRecord,          "Bad record number"),
        errcode (ErrFunctionCall,       "Illegal function call"),
        errcode (ErrSocket,             "Socket error"),
        errcode (ErrRenameFile,         "Rename file error"),
        errcode (ErrOperatingSystem,    "Operating system error"),
        errcode (ErrPastEof,            "Input past EOF"),
        errcode (ErrNoGraphics,         "Graphics mode required"),
};

errcode * table_end= table + sizeof (table);

class is_err {
public:
	is_err (BlErrNo err) : err (err)
	{ }
	bool operator () (const errcode & ec) const
	{ return ec.err == err; }
private:
	BlErrNo err;
};

} // namespace

std::string ErrStr (BlErrNo err)
{
	const errcode * perr= std::find_if (table, table_end, is_err (err) );
	if (perr != table_end)
		return perr->str;
	std::ostringstream strbuf;
	strbuf << "Error " << err;
	return strbuf.str ();
}

std::ostream & operator << (std::ostream & os, const BlError & bl)
{
	os << ErrStr (bl.err);
	const BlLineNumber line= bl.getpos ().getnum ();
	if (line != 0)
		os << " in " << line;
	os << '\n';
	return os;
}

// Fin de error.cpp