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Lexical Analysis
Volume Number:6
Issue Number:5
Column Tag:Language Translation

Ambiguities and Lexical Analysis

By Clifford Story, Mount Prospect, IL

Part III. Ambiguities, Etc.

A. Introduction

This is the third part in my series on Language Translation. Language translation has three phases: lexical analysis, parsing, and code generation. The first two parts have dealt with building parsers using YACC; this is the final installment on that subject.

That will take up only about half the article. The remainder will begin the new topic of lexical analysis by presenting a skeleton filter tool.

B. Parsing

I now conclude parsing with a couple of miscellaneous topics. The first is a simple way to handle ambiguities in a grammar. Then comes the horrible question of error detection and reporting.

B(1). Ambiguities

Parser ambiguities, you may recall, are spots in the parse table where YACC’s generation algorithm would place a shift and a reduction, or two reductions. A naive grammar would generate an ambiguity when considering the input string

2 + 3 * 4

since it isn’t clear whether this means (2 + 3) * 4 or 2 + (3 * 4).

We faced this problem in the first part and solved it by re-writing the grammar to eliminate the ambiguity. YACC offers another way of handling ambiguities (also known as shift/reduce and reduce/reduce conflicts).

B(1)(a). YACC’s Default Rule

First, something you should know: YACC will work through any conflicts that it finds and produce a non-ambiguous grammar for you. It resolves conflicts automatically, and will only issues warnings, not errors.

Unfortunately, it does this by making assumptions about what you intended, and these assumptions need not be correct. You can get a grammar that simply does not do what you meant it to do, despite the lack of error messages. In my opinion, this is a design flaw in YACC; conflicts should be fatal errors.

Even worse, MACYACC (see the first part for a review) uses an inordinately complicated rule for resolving conflicts. Unix YACC uses a very simple rule, so you can guess what it’s going to do. MACYACC, no such luck.

Therefore, YOU SHOULD ALWAYS REACT TO CONFLICT WARNINGS AS IF THEY WERE FATAL ERRORS!

B(1)(b). Operator Precedence

Remember, conflicts arise when the parser doesn’t know which operation to perform first, as in the 2 + 3 * 4 example. We intelligent humans know that multiplication comes before addition: multiplication has a higher precedence than addition. The conflict is easily and correctly resolved if YACC knows the order of precedence among all operators in the grammar.

All that need be done is tell YACC:

/* 1 */

%left ‘+’ ‘-’
%left ‘*’ ‘/’

Multiplication and division have the same precedence (because they are on the same line), and higher precedence than addition and subtraction (because their line is after addition and subtraction’s line). That solves the problem (read on for an explanation of the “left” business).

But what about strings like

2 - 3 + 4

Is that 2 - (3 + 4) or (2 - 3) + 4? The above rules don’t seem to say, since subtraction and addition have the same precedence.

B(1)(c). What is Associativity?

Good question. In a string of the form

... • ID • ...

where ‘•’ is an operator and ‘ID’ an identifier, the • to the left of the ID will have a higher precedence than the • to the right if • is left-associative; and conversely. Thus,

2 - 3 - 4

is conventionally -5 because subtraction is left-associative. If it were right-associative, 2 - 3 - 4 would equal 2 - (3 - 4), or 3. Just about everything is left-associative.

So associativity defines order of evaluation among operators on the same level of operator precedence. And the line

%left ‘+’ ‘-’

says that addition and subtraction are left-associative among one another.

YACC also includes keywords %right, which means just what you might think, and %nonassoc, which means constructs of the form

... • ID • ...

are illegal (think of logical operators).

B(1)(d). The Lonely Minus...

There’s one more thing to worry about: unary operators. The classic example is the minus sign. Do you remember my asking why a hex calculator was easier to write than a decimal calculator? The answer is that a hex calculator doesn’t have to deal with unary minus...

The problem arises because the minus sign is used for both unary and binary operators (negation and subtraction). When we assign it a precedence in the %left statement, we’re thinking about subtraction, so we give it a lower precedence than multiplication and division. But negation should have the same precedence as multiplication and division.

The solution is to give a grammar rule a precedence. This can be done with the %prec keyword:

expr : ‘-’ expr %prec ‘*’

gives this rule the same precedence as multiplication. Thus, unary minus will have the right precedence, and everything is at last conflict-free.

B(1)(e).  An Example

%token  NUM
%left   ‘+’ ‘-’
%left   ‘*’ ‘/’
%left   MINUS

%%

prob  : expr ‘\n’
 {
 printf(“\t= %d\n”, $1);
 return(0);
 }
 
 ;

expr  : expr ‘+’ expr
 {
 $$ = $1 + $3;
 }
 
 | expr ‘-’ expr
 {
 $$ = $1 - $3;
 }
 
 | expr ‘*’ expr
 {
 $$ = $1 * $3;
 }
 
 | expr ‘/’ expr
 {
 $$ = $1 / $3;
 }
 
 | ‘-’ expr %prec MINUS
 {
 $$ = - $2;
 }
 
 | ‘(‘ expr ‘)’
 {
 $$ = $2;
 }
 
 | NUM
 {
 $$ = $1;
 }
 
 ;

%%

/***************************************/
#include “stdio.h”
#include “ctype.h”
#include “string.h”
/***************************************/
char    *input;
char    *token;
/***************************************/

#define yyerror(x)
 {
 printf(“\t%s [%s]\n”, x, token);
 return(0);
 }

yyparse();
int yylex();
 
/***************************************/
void main(int argc, char *argv[])
 {
 
 char   thestring[256];
 
 if (argc < 1)
 printf(“\tImpossible error!\n”);
 else if (argc > 2)
 printf(“\tHey!  One at a time!\n”);
 else if (argc == 2)
 {
 input = argv[1];
 yyparse();
 }
 else
 {
 printf(“? “);
 while (strlen(gets(thestring)) > 2)
 {
 input = &thestring[2];
 yyparse();
 printf(“? “);
 }
 }
 }
 
/***************************************/
int yylex()
 {
 
 token = strtok(input, “ “);
 input = 0;
 
 if (token == 0)
 return(‘\n’);
 else if (sscanf(token, “%d”, &yylval) == 1)
 return(NUM);
 else
 return(token[0]);
 
 }
/***************************************/

B(2). Catching Errors

You may have noticed that Pascal compilers write real error messages, while C compilers write error messages more cryptic than C itself. There’s a reason for this: Pascal compilers use recursive-descent parsers, while C compilers use table-driven parsers. Recursive-descent parsers are the sort of parsers a person might naturally write: get the next token; if it’s a ‘+’, do this, else get the next token and do that, and so on. A location in the code of the parser corresponds to a particular grammar structure in the input string, so it’s easy to insert appropriate error messages. Table-driven parsers make things more difficult. Ever seen an error message to the effect “Need an lval”? That’s a sign of the parser, not the language; from the YACC global yylval, you can probably guess what an lval is.

So writing meaningful error messages in a YACC-generated parser is a real problem.

B(2)(a). Semantic Errors

Semantic errors are easy. These are illegal operations, like division by zero, and other violations of data types (overflow, writing past the end of an array, and so forth).

The decimal calculator provides the opportunity to divide by zero. Let’s catch this error, and issue an error message instead. Division occurs in only one grammar rule:

/* 3 */

expr  | expr ‘/’ expr
 {
 $$ = $1 / $3;
 }

Just insert an operand check in the generated code:

/* 4 */

expr  | expr ‘/’ expr
 {
 if ($3 != 0)
 $$ = $1 / $3;
 else
 {
 printf(“Divide by zero!\n”);
 return(0);
 }
 }

I’m using a cheap trick here; the return(0) means abort. This is ok, because the calculator evaluates one expression at a time, and an error should cause an abort. But if this were a compiler, detecting a single error should not kill the compile; I want to know about ALL the errors.

B(2)(b). Illegal Characters

The language’s character set has nothing to do with the grammar, and hence nothing to do with the parser. It is entirely in the control of the lexical analyzer. And, of course, it’s easy for the lexical analyzer to catch illegal characters. But how can it report them?

Here’s my solution. First, I declare a new token at the top of the input file:

/* 5 */

%token  ILLEGAL

None of the grammar rules use this token, so should the lexical analyzer return it, the parser must sense an error.

Now, to get an error message out of this! I’m going to continue to declare the yyerror routine as a macro, so it can use the parser’s local variables and also abort the parser. Then I’m going to create a new error routine that yyerror will call, passing a couple of those interesting locals. The two I want are ‘tmpstate’, the current state of the parser, and ‘pcyytoken’, the type of the last token returned by yylex(). The declarations look like this:

/* 6 */

#define yyerror(x)
 {
 errordisplay(tmpstate, pcyytoken);
 return(0);
 }
void errordisplay(int state,
 int tokentype);

Then, in the errordisplay() routine, if ‘tokentype’ equals ILLEGAL, I print an appropriate message.

B(2)(c). Syntactic Errors

Errors of syntax are the hard ones (and my development of this topic has not been helped by my outliner’s just destroying my first approach to it. Especially since I wrote the outliner... A word of advice to aspiring Mac programmers: do not neglect the grow zone routine.) The problem is that these errors are detected by a table that we didn’t write, instead of nice readable code that we did.

But we can still zero in on the specific error. We begin with the .out file. If there’s an error in state 0, we know why: the parser was expecting a number, a -, or a (, but it got something else instead. So instead of saying just “syntax error”, we say “Expecting a number, - or (!”. We can do the same for each state, and write errordisplay() as follows:

/* 7 */

void errordisplay(int state,
 int tokentype)
 {
 
 if (tokentype == ILLEGAL)
 printf(“\tIllegal character!\n”);
 else switch (state)
 {
 
 case 0:
 case 3:
 case 4:
 case 7:
 case 8:
 case 9:
 case 10:
 printf(“\tExpecting a number,”
 “‘-’ or ‘(’!\n”);
 break;
 
 case 2:
 printf(“\tExpecting an “
 “operator or end “
 “of input!\n”);
 break;
 
 case 12:
 printf(“\tExpecting an “
 “operator or ‘)’!\n”);
 break;
 
 case 13:
 case 14:
 printf(“\tExpecting a ‘*’ “
 or ‘/’!\n”);
 break;
 
 default:
 printf(“\tImpossible error!  “
 “State = %d, token = %d\n”,
 state, tokentype);
 break;
 
 }
 
 }

All right, but we can do better than that. For example, since the parser is in state 0 only when it is reading the first token, an error in state zero means that the token is wrong for the beginning of input, so we might write something more to the point, like “An expression must begin with a number, - or (!”. Similarly, we can look closer at the other states and get a better idea of just what is going on in each. We can use the token type to further focus on the error. And so on.

And we can also keep track of just where in the input we are, so we can point to the location of the error:

? 2 - 3 4
        ^

Expecting an operator or end of input!

B(3). Last Words on YACC

And that’s it for YACC. Which is not to say that nothing in the remainder of the series will rely on YACC; on the contrary. But I will assume that my audience is now familiar with the tool and introduce grammar descriptions and such without apology.

The next topic is lexical analysis. And since I’ve got some space left this month, I’ll launch into it with a skeleton filter program.

C. Lexical Analysis

Next time, I will move on to lexical analysis, and replace my calculator example with a file filter. Filter programs are somewhat unusual in the Macintosh world, so perhaps a definition is appropriate: a filter program is one that reads one filter, massages it in some way, and writes the result. Such programs are common under Unix, where simple programs can be strung together in batch files with IO redirection and piping to create much more powerful utilities. For an example, see the discussion of Steve Johnson’s spell utility on page 139 of Jon Bentley’s Programming Pearls.

The calculator example I’ve used so far is not a filter, since it works from direct user input on the command line. It looks like the rest of this series will use filters, however; first with the lexical analysis examples, and then with the inline assembler. What I’m going to do now is develop a basic identity filter, to settle some issues once and for all, so I can then ignore them and concentrate on language translation.

C(1). Command Line

The first problem is reading the command line. I want the tool to read either one or more files named on the command line, or standard input if there aren’t any named input files. I want it to write to a named output file, or to standard output if none is named. And I want to be able to set a language type (for reasons that won’t become clear until next month) with command line options.

Recall that MPW passes the command line as an array of strings. The first string, argv[0], is the name of the tool, and the rest are the individual arguments.

C(1)(a). Input Files

Input files are specified on the command line by name alone, with no special flags. If a name appears unaccompanied by any flag, it is by default an input file. The tool can read arbitrarily many input files; if none are specified, then it reads standard input (which can come from IO redirection).

So I’m going to have an integer variable called “input” which I will initialize to the standard input unit. Then I’ll walk through the argument list, and if I find an input file, I will open it (using the “input” variable for its unit), append it to my input buffer, and close it. If, after reading the entire command line, “input” is still equal to standard input, then I know that no input files were named, and so I’ll read standard input into the buffer.

C(1)(b). Options

Options are command arguments that begin with a hyphen (this doesn’t have to be so; I have written a tool with an almost natural-language command line but -options are customary and easy to parse).

There are two kinds of options: the output file, and true options (the name of the output file isn’t a true option, of course, but it’s specified with option syntax).

C(1)(b)(i). Output File

The tool can write one output file, or write to standard output. A named output file is specified with a “-o” option followed by the name of the file.

Similarly to output, I have an integer variable called “output”, initially set to the standard output unit. If an output file is named on the command line, then I open it, and set “output” to its unit number. If “output” isn’t standard output, then I know an output file is already open, so I print a warning and ignore the new file.

C(1)(b)(ii). Language

I won’t be using the language option this month but I might as well get it in here anyway. The language can be either Pascal or C. Pascal is the default; it is reset by the first named input file with either a “.p” or “.c” extension, and this can be overridden with either a “-p” or “-c” command option.

First, I’ll declare a special type, “codetype”:

/* 8 */

typedef enum
 {
 nocode,
 pascalcode,
 ccode
 } codetype;

and a variable, “language” of type codetype, initially “nocode”. This indicates that the language has not been set.

As I walk though the command line, if I find an input file, “language” is still “nocode”, and the file name ends in either “.p” or “.c”, then I’ll set “language” accordingly. Thus, only the first such file can set the language.

If, on the other hand, I find a “-p” or “-c” option, I will set “language” accordingly, regardless of any previous setting. The options override filename conventions. (I don’t check for multiple options; the last one controls.)

Finally, if “language” is still “nocode” after reading the entire command line, then I set it to the default, Pascal.

C(2). IO Buffering

In the interests of speed, I’ll buffer both input and output. If you don’t think this makes a difference, just re-write the tool without buffering!

Input buffering is easy: I just read input, in 1K chunks, into a single buffer, which I can re-size as necessary to accommodate the amount to read. The MPW interface doesn’t provide any way to get the file size before reading it (not surprising, I guess; what’s the “size” of standard input?).

Output buffering is a bit more complex. This is an identity filter, so I just copy the input without modification to the output buffer. When the output buffer fills up, I write 1K of it to the output file, and shift what’s left to the front of the buffer.

C(3). The Program

Here’s the code. The file “managers” is a load file containing all the C include files; this makes compilation of the program faster.

/* 9 */

// Filter.c - Skeleton MPW filter tool
 
#pragma load “managers”
 
// Constants and Macros
 
#define nil 0
 
#define stdinfd  0
#define stdoutfd 1
#define stderrfd 2
 
#define stdunit(x) ((x >= stdinfd) && (x <= stderrfd))
#define notstdunit(x)(x > stderrfd)

#define nombuffsize1024
#define truebuffsize 1200
 
// Types
typedef enum {false, true} logical;

typedef enum
 {
 nocode,
 pascalcode, 
 ccode
 } codetype;
 
// Prototypes
 void initmac();
 int openoutput(char *thename, int output);
 int readinput(int input, Handle inbuffer, int buffersize);
 int filter(char *inbuffer, int buffersize, int output, 
 codetype language);
 int writeoutput(int output, char *outbuffer, int buffersize);
 
// main
// ----
// the “main” routine reads and
// interprets the command line,
// concatenates input files into an
// input buffer, opens the output
// file, and calls the “filter”
// routine to write the output.
 
int main(int argc, char *argv[])
 {
 int    index;
 int    input;
 int    output;
 codetype language;
 Handle inbuffer;
 int    buffersize;
 char   *thetail;
 
 initmac();
 
// “input” is the fd of the input file,
// initially stdin “output” is the fd
// of the output file, initially
// stdout “language” is the language
// to parse, initially unknown
 
 input = stdinfd;
 output = stdoutfd;
 language = nocode;
 
// “inbuffer” is the input buffer,
// initially empty but able to grow
// “buffersize” is the size of “inbuffer”
 
 inbuffer = NewHandle(0);
 buffersize = 0;
 
// command line interpreter: loop through command options
 
 for (index = 1; index < argc; index++)
 {
 if (argv[index][0] == ‘-’)
 {
 switch (argv[index][1])
 {
 
// “-p” and “-c” options set language
// type; these override any previous setting
 
 case ‘P’:
 case ‘p’:
 language = pascalcode;
 break;
 
 case ‘C’:
 case ‘c’:
 language = ccode;
 break;
 
 case ‘O’:
 case ‘o’:
 output = openoutput(
 argv[++index], output);
 if (output < 0)
 {
 fprintf(stderr, “Error - Unable”
 “ to open output  file %s!\n”,
 argv[index]);
 exit(2);
 }
 break;
 
 default:
 fprintf(stderr, “Error - Unknown option %s\n”,
  argv[index]);
 exit(2);
 break;
 
 }
 
 }
 else
 {
 
// if “language” has not changed since
// initialization, set “language”
// according to file name (the first
// input file thus determines language type)
 
 if (language == nocode)
 {
 thetail = argv[index] + strlen(argv[index]) - 2;
 if (strcmp(thetail, “.p”) == 0)
 language = pascalcode;
 else if (strcmp(thetail, “.c”) == 0)
 language = ccode;
 }
 
// open the input file (after this step,
// “input” will NOT contain a standard
// unit number) and read it into the input buffer
 
 input = open(argv[index], O_RDONLY);
 if (input < 0)
 {
 fprintf(stderr, “Error - Unable to open input”
 “file %s!\n”, argv[index]);
 exit(2);
 }
 
 buffersize = readinput(input, inbuffer, buffersize);
 if (buffersize < 0)
 {
 fprintf(stderr, “Error -  Reading from %s!\n”,
 argv[index]);
 exit(2);
 }
 
 close(input);
 
 }
 }
 
// if “input” is still a standard unit
// number, then no input file was
// opened, and input must be from standard input
 
 if (stdunit(input))
 {
 buffersize = readinput(input,
 inbuffer, buffersize);
 if (buffersize < 0)
 {
 fprintf(stderr, “Error - Reading from standard”
 “ input!\n”);
 exit(2);
 }
 }
 
// if “language” is still unknown, set it to Pascal
 
 if (language == nocode)
 language = pascalcode;
 
// the routine “filter” does the real work of the program
 
 HLock(inbuffer);
 filter(*inbuffer, buffersize, output, language);
 HUnlock(inbuffer);
 
// wrapup:  close “output” first if the program opened it
 
 DisposHandle(inbuffer);
 
 if (notstdunit(output))
 close(output);
 
 exit(0);
 }
 
// initmac
// ------
// initialize any necessary managers and whatnot.
 
void initmac()
 {
 
 InitGraf((Ptr)&qd.thePort);
 SetFScaleDisable(true);
 
 InitCursorCtl(nil);
 }
 
// openoutput
// ----------
// open the output file.  returns the
// fd or, if an error occurs, the
// error flag.
 
int openoutput(char *thename, int output)
 {
 FInfo  theinfo;
 
// if “output” is not a standard unit,
// then an output file must have already be open
 
 if (notstdunit(output))
 {
 fprintf(stderr, “Warning - additional output file %s”
 “ ignored!\n”, thename);
 return(output);
 }

// open the output file for writing
// (O_WRONLY), creating it if
// necessary (O_CREAT) and
// zeroing it otherwise (O_TRUNC)
 
 output = open(thename, O_WRONLY + O_CREAT + O_TRUNC);
 if (output < 0)
 return(output);

// if the file was created by “open”, it
// will be untyped, so set the type to TEXT and MPS
 
 if (getfinfo(thename, 0, &theinfo))
 {
 fprintf(stderr, “Warning - unable to get info for output file %s!\n”, 
thename);
 return(output);
 }
 
 theinfo.fdType = ‘TEXT’;
 theinfo.fdCreator = ‘MPS ‘;
 
 if (setfinfo(thename, 0, &theinfo))
 fprintf(stderr, “Warning - unable to set info for output file %s!\n”, 
thename);
 
 return(output);
 }
 
// readinput
// --------
// this routine appends an input file
// to the input buffer and returns
// the new size of the buffer or, if
// a read error occurs, the error flag.
 
int readinput(int input, Handle inbuffer, int buffersize)
 {
 int    readsize;
 
 SetHandleSize(inbuffer, buffersize + 1024);
 HLock(inbuffer);
 
 while ((readsize = read(input,
 *inbuffer + buffersize, 1024)) > 0)
 {
 buffersize += readsize;
 HUnlock(inbuffer);
 SetHandleSize(inbuffer, buffersize + 1024);
 HLock(inbuffer);
 }
 
 if (readsize < 0)
 return(readsize);
 
 HUnlock(inbuffer);
 SetHandleSize(inbuffer, buffersize + 1024);
 
 return(buffersize);
 }
 
// filter
// ------
// this routine does the main work of
// the program, which in this case
// consists of simply writing the
// input buffer to the output file.
 
int filter(char *inbuffer, int buffersize, int output,
 codetype language)
 {
#pragma unused(language)
 
 int    inposition;
 int    outposition;
 char   outbuffer[truebuffsize];
 unsigned char thechar;
 int    writesize;
 
// “inposition” keeps track of the
// current position in the input
// buffer, initially at the beginning
// “outposition” keeps track of the
// current position in the output
// buffer, initially at the beginning
 
 inposition = 0;
 outposition = 0;
 
 while (inposition < buffersize)
 {
// copy input to the output buffer, one character at a time
 thechar = *(inbuffer + inposition++);
 outbuffer[outposition++] = thechar;
 
// when the output buffer fills up, write it to output
 if (outposition >= nombuffsize)
 outposition = writeoutput(
 output, outbuffer, 
 outposition);
 if (outposition < 0)
 return(outposition);
 
 }
 
// write whatever is left in the buffer
// directly to output
 
 writesize = write(output, outbuffer, outposition);
 return(writesize);
 }
 
// writeoutput
// ----------
// this routine flushes the output 
// buffer by writing it to the output
// file.  It returns the new size of
// the buffer or, if a write error
// occurs, the error flag.
 
int writeoutput(int output, char *outbuffer, int buffersize)
 {
 int    writesize;
 
 writesize = write(output, outbuffer, nombuffsize);
 
 if (writesize < 0)
 return(writesize);
 
 buffersize -= writesize;
 BlockMove(outbuffer + writesize, outbuffer, buffersize);
 
 return(buffersize);
 }

D. Conclusion

Next time I’ll expand the Filter tool by adding a state machine to control the transfer of data from the input buffer to the output buffer. I’ll assume you’ve got the code just above, and won’t repeat it, except for the “filter” routine. So hang on to this issue of MacTutor!

 

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I Am The Hero 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: I Am The Hero is a pixel art, beat 'em up, fighting game that tells the story of a "Hero" with a glorious but mysterious past.... | Read more »
Kauldron (Music)
Kauldron 1.0 Device: iOS Universal Category: Music Price: $3.99, Version: 1.0 (iTunes) Description: Kauldron is our warmest sounding, punchiest synth yet! A completely new modeling technology, combined with carefully designed... | Read more »
Lineage II: Revolution is mobile’s bigge...
NCSoft’s hit fantasy MMORPG series has just made the leap to mobile with the help of Netmarble in Lineage II: Revolution. With over 1.5 million players having already pre-registered ahead of the game’s launch, Revolution hit the app stores... | Read more »
Swing skilfully in new physics-based pla...
Sometimes it’s the most difficult of obstacles that can be the most rewarding. One game hoping to prove this is OCMO, the new tough but fair platformer from developers Team Ocmo. Primed to set every speedrunner’s pulse racing, as an otherworldly... | Read more »
RPGolf (Games)
RPGolf 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Once upon a time, the kingdom was a land of peace, harmony, and an all-consuming passion for the greatest sport - GOLF. Everyone in the... | Read more »
Everything you need to know about Fire E...
Fire Emblem Heroes is getting its biggest update yet as Nintendo unveiled Book II last night, featuring a whole new set of story missions and yes, collectible heroes. The update's not out just yet, but here's what you can expect when the new... | Read more »
The biggest updates out this week - Nove...
A big game update is always a treat. Multiply that by four and you're having a really good week. Those weeks don't come around very often, but you're in luck. This chilly mid-November is chock full updates for some of your favorite titles, and they... | Read more »
Ocmo (Games)
Ocmo 1.0.13 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.13 (iTunes) Description: Ocmo is an award winning ninja rope platformer that challenges even hardcore gamers. Fluid movement, physics based gameplay and... | Read more »

Price Scanner via MacPrices.net

Early Black Friday sale: Apple iMacs for up t...
B&H Photo has 27-inch iMacs in stock and on sale for up $130-$150 off MSRP including free shipping. B&H charges sales tax in NY & NJ only: – 27″ 3.8GHz iMac (MNED2LL/A): $2149 $150 off... Read more
Apple restocks refurbished Mac minis starting...
Apple has restocked Certified Refurbished Mac minis starting at $419. Apple’s one-year warranty is included with each mini, and shipping is free: – 1.4GHz Mac mini: $419 $80 off MSRP – 2.6GHz Mac... Read more
Save on 12″ MacBooks, Apple refurbished model...
Apple has Certified Refurbished 2017 12″ Retina MacBooks available for $200-$240 off the cost of new models. Apple will include a standard one-year warranty with each MacBook, and shipping is free.... Read more
Early Holiday sale: 12″ iPad Pros for up to $...
B&H Photo has 12″ iPad Pros on sale today for up to $130 off MSRP. Shipping is free, and B&H collects no sales tax outside NY & NJ: – 12″ 64GB WiFi iPad Pro: $749, save $50 – 12″ 256GB... Read more
Holiday sale prices on Apple 13″ MacBook Pros...
B&H Photo has 2017 13″ MacBook Pros in stock today and on sale for $100-$150 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook Pro... Read more
Sale: 13″ MacBook Airs starting at $899, $100...
B&H Photo has 2017 13″ MacBook Airs on sale today for $100 off MSRP including free shipping. B&H charges NY & NJ sales tax only: – 13″ 1.8GHz/128GB MacBook Air (MQD32LL/A): $899, $100 off... Read more
Week’s Best Deal on 13″ MacBook Pros: Apple r...
Apple has a full line of Apple Certified Refurbished 2017 13″ MacBook Pros available for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
Deal: 15″ 2.6GHz MacBook Pro for $1799 w/free...
B&H Photo has clearance 2016 15″ 2.6GHz Touch Bar MacBook Pros in stock today and available for $600 off original MSRP. Shipping is free, and B&H charges NY & NJ sales tax only: – 15″ 2.... Read more
Black Friday pricing on the 1.4GHz Mac mini....
MacMall has the 1.4GHz Mac mini on sale for $399 including free shipping. Their price is $100 off MSRP (20% off), and it’s the lowest price for available for this model from any reseller. MacMall’s... Read more
Early Black Friday deal: 15″ Apple MacBook Pr...
B&H Photo has 15″ MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges sales tax in NY & NJ only: – 15″ 2.8GHz MacBook Pro Space Gray (MPTR2LL/A): $2199, $200... Read more

Jobs Board

AppleCare Support Engineer for *Apple* Medi...
…Summary AppleCare Engineering, Software & Services, is a group that works to represent Apple 's World Wide contact centers and Apple 's customers to groups within Read more
Site Reliability Engineer, *Apple* Pay - Ap...
Job Summary The Apple Pay Site Reliability Engineering Team is hiring for multiple roles focused on the front line customer experience and the back end integration Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 86078534 Fairless Hills, Pennsylvania, United States Posted: 07-Jul-2017 Weekly Hours: 40.00 **Job Summary** As an Apple Read more
Digital Marketing Media Planner, *Apple* Se...
Job Summary Apple is looking to add a hyper-organized, strategic, and fast-learning member to its Digital Marketing team to help support Apple Services ( Apple Read more
*Apple* Retail - Multiple Positions - Apple...
SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
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