stdin.readByteSync has recently been added to Dart.
Using stdin.readByteSync for data entry, I am attempting to allow a default value and if an entry is made by the operator, to clear the default value. If no entry is made and just enter is pressed, then the default is used.
What appears to be happening however is that no terminal output is sent to the terminal until a newline character is entered. Therefore when I do a print() or a stdout.write(), it is delayed until newline is entered.
Therefore, when operator enters first character to override default, the default is not cleared. IE. The default is "abc", data entered is "xx", however "xxc" is showing on screen after entry of "xx". The "problem" appears to be that no "writes" to the terminal are sent until newline is entered.
While I can find an alternative way of doing this, I would like to know if this is the way readByteSync should or must work. If so, I’ll find an alternative way of doing what I want.
// Example program //
import 'dart:io';
void main () {
int iInput;
List<int> lCharCodes = [];
print(""); print("");
String sDefault = "abc";
stdout.write ("Enter data : $sDefault\b\b\b");
while (iInput != 10) { // wait for newline
iInput = stdin.readByteSync();
if (iInput == 8 && lCharCodes.length > 0) { // bs
lCharCodes.removeLast();
} else if (iInput > 31) { // ascii printable char
lCharCodes.add(iInput);
if (lCharCodes.length == 1)
stdout.write (" \b\b\b\b chars cleared"); // clear line
print ("\nlCharCodes length = ${lCharCodes.length}");
}
}
print ("\nData entered = ${new String.fromCharCodes(lCharCodes).trim()}");
}
Results on Command screen are :
c:\Users\Brian\dart-dev1\test\bin>dart testsync001.dart
Enter data : xxc
chars cleared
lCharCodes length = 1
lCharCodes length = 2
Data entered = xx
c:\Users\Brian\dart-dev1\test\bin>
I recently added stdin.readByteSync and readLineSync, to easier create small scrips reading the stdin. However, two things are still missing, for this to be feature-complete.
1) Line mode vs Raw mode. This is basically what you are asking for, a way to get a char as soon as it's printed.
2) Echo on/off. This mode is useful for e.g. typing in passwords, so you can disable the default echo of the characters.
I hope to be able to implement and land these features rather soon.
You can star this bug to track the development of it!
This is common behavior for consoles. Try to flush the output with stdout.flush().
Edit: my mistake. I looked at a very old revision (dartlang-test). The current API does not provide any means to flush stdout. Feel free to file a bug.
Related
CONCLUSION:
For some reason the flow wouldn't let me convert the incoming message to a BLOB by changing the Message Domain property of the Input Node so I added a Reset Content Descriptor node before the Compute Node with the code from the accepted answer. On the line that parses the XML and creates the XMLNSC Child for the message I was getting a 'CHARACTER:Invalid wire format received' error so I took that line out and added another Reset Content Descriptor node after the Compute Node instead. Now it parses and replaces the Unicode characters with spaces. So now it doesn't crash.
Here is the code for the added Compute Node:
CREATE FUNCTION Main() RETURNS BOOLEAN
BEGIN
DECLARE NonPrintable BLOB X'0001020304050607080B0C0E0F101112131415161718191A1B1C1D1E1F7F808182838485868788898A8B8C8D8E8F909192939495969798999A9B9C9D9E9FA0A1A2A3A4A5A6A7A8A9AAABACADAEAFB0B1B2B3B4B5B6B7B8B9BABBBCBDBEBFC0C1C2C3C4C5C6C7C8C9CACBCCCDCECFD0D1D2D3D4D5D6D7D8D9DADBDCDDDEDFE0E1E2E3E4E5E6E7E8E9EAEBECEDEEEFF1F2F3F4F5F6F7F8F9FAFBFCFDFEFF';
DECLARE Printable BLOB X'20202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020';
DECLARE Fixed BLOB TRANSLATE(InputRoot.BLOB.BLOB, NonPrintable, Printable);
SET OutputRoot = InputRoot;
SET OutputRoot.BLOB.BLOB = Fixed;
RETURN TRUE;
END;
UPDATE:
The message is being parsed as XML using XMLNSC. Thought that would cause a problem, but it does not appear to be.
Now I'm using PHP. I've created a node to plug into the legacy flow. Here's the relevant code:
class fixIncompetence {
function evaluate ($output_assembly,$input_assembly) {
$output_assembly->MRM = $input_assembly->MRM;
$output_assembly->MQMD = $input_assembly->MQMD;
$tmp = htmlentities($input_assembly->MRM->VALUE_TO_FIX, ENT_HTML5|ENT_SUBSTITUTE,'UTF-8');
if (!empty($tmp)) {
$output_assembly->MRM->VALUE_TO_FIX = $tmp;
}
// Ensure there are no null MRM fields. MessageBroker is strict.
foreach ($output_assembly->MRM as $key => $val) {
if (empty($val)) {
$output_assembly->MRM->$key = '';
}
}
}
}
Right now I'm getting a vague error about read only messages, but before that it wasn't working either.
Original Question:
For some reason I am unable to impress upon the senders of our MQ
messages that smart quotes, endashes, emdashes, and such crash our XML
parser.
I managed to make a working solution with SQL queries, but it wasted
too many resources. Here's the last thing I tried, but it didn't work
either:
CREATE FUNCTION CLEAN(IN STR CHAR) RETURNS CHAR BEGIN
SET STR = REPLACE('–',STR,'–');
SET STR = REPLACE('—',STR,'—');
SET STR = REPLACE('·',STR,'·');
SET STR = REPLACE('“',STR,'“');
SET STR = REPLACE('”',STR,'”');
SET STR = REPLACE('‘',STR,'&lsqo;');
SET STR = REPLACE('’',STR,'’');
SET STR = REPLACE('•',STR,'•');
SET STR = REPLACE('°',STR,'°');
RETURN STR;
END;
As you can see I'm not very good at this. I have tried reading about
various ESQL string functions without much success.
So in ESQL you can use the TRANSLATE function.
The following is a snippet I use to clean up a BLOB containing non-ASCII low hex values so that it then be cast into a usable character string.
You should be able to modify it to change your undesired characters into something more benign. Basically each hex value in NonPrintable gets translated into its positional equivalent in Printable, in this case always a full-stop i.e. x'2E' in ASCII. You'll need to make your BLOB's long enough to cover the desired range of hex values.
DECLARE NonPrintable BLOB X'000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F';
DECLARE Printable BLOB X'2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E2E';
SET WorkBlob = TRANSLATE(WorkBlob, NonPrintable, Printable);
BTW if messages with invalid characters only come in every now and then I'd probably specify BLOB on the input node and then use something similar to the following to invoke the XMLNSC parser.
CREATE LASTCHILD OF OutputRoot DOMAIN 'XMLNSC'
PARSE(InputRoot.BLOB.BLOB CCSID InputRoot.Properties.CodedCharSetId ENCODING InputRoot.Properties.Encoding);
With the exception terminal wired up you can then correct the BLOB's of any messages containing parser breaking invalid characters before attempting to reparse.
Finally my best wishes as I've had a number of battles over the years with being forced to correct invalid message content in the "Integration Layer" after all that's what it's meant to do.
I am trying to write a program that will understand a language where embedded comments are allowed. Such as:
/* Here's a comment
/* This comment is further embedded */ second comment is closed
Must close first comment */
This should be recognized as a comment (and as such not stop at the first */ it sees unless it has only seen 1 comment opening prior).
This would be an easy issue to fix in C, I could simply have a counter that incremented when it saw comment opens and decrements when it sees a comment close. If the counter is at 0, we're in "code section".
However, without having state in Haskell, it's a little more challenging.
I've read up on monadUserState which supposedly allows to keep track of a state for this exact type of parsing. However, I can't find very much reading material on it aside from the tutorial page on alex.
When I try to compile it gives the error
templates\wrappers.hs:213:16: Not in scope: `alexEOF`
It should be noted that I directly changed from the "basic" wrapper to the "monadUserState" without changing my code (I don't know what to add in order to use it). It says that this must be initialized in the user code:
data AlexState = AlexState {
alex_pos :: !AlexPosn, -- position at current input location
alex_inp :: String, -- the current input
alex_chr :: !Char, -- the character before the input
alex_bytes :: [Byte], -- rest of the bytes for the current char
alex_scd :: !Int, -- the current startcode
alex_ust :: AlexUserState -- AlexUserState will be defined in the user program
}
I'm a bit of a lexxing noob and I'm not at all sure what I should be adding here to make it at least compile... then I can worry about the logic of the thing.
Update: Working example available here: http://lpaste.net/119212
The file "tiger.x" (link) in the alex github repo contains an example of how to track embedded comments using the monadUserState wrapper.
Well, unfortunately that example doesn't compile but the ideas there should work.
Basically, these lines perform embedded comment processing:
<0> "/*" { enterNewComment `andBegin` state_comment }
<state_comment> "/*" { embedComment }
<state_comment> "*/" { unembedComment }
<state_comment> . ;
<state_comment> \n { skip }
As for alexEOF, the idea is to add an EOF token to your token data type:
data Tokens = ... | EOF
and define alexEOF as:
alexEOF = return EOF
See the file tests/tokens_monadUserState_bytestring.x in the alex repo for an example of this.
I've created a Dart console app and need to process keycodes like Arrow keys and function keys from stdin? The samples I've seen are typically String based :
Stream readLine() => stdin.transform(UTF8.decoder).transform(new LineSplitter());
readLine().listen(processLine);
I modified the above sample hoping to get the raw ints like this:
Stream readInts() => stdin;
readInts().listen(processInts);
void processInts(List<int> kbinput) {
for (int i=0;i<kbinput.length;i++){
print ("kbinput:${kbinput[i]}");
}
}
It seems stdin provides only printable characters and not all ascii keycodes. If it is not possible from stdin, can I create & load a stream within my native extension with the keycodes? How can my console app get to the ascii keycodes of any keypress? Thanks for your help!
One way would be
import 'dart:io' as io;
import 'dart:convert' show UTF8;
void main() {
io.stdin.echoMode = false;
var input;
while(input != 32) { // leave program with [Space][Enter]
input = io.stdin.readByteSync();
if(input != 10) print(input); // ignore [Enter]
}
io.stdin.echoMode = true;
}
but it only returns a value after Enter is pressed.
For one key press it returns from one up to three bytes.
It seems it's not easy to get a keystroke from console without pressing Enter
see Capture characters from standard input without waiting for enter to be pressed for more details.
You could create a native extension that implements the suggested solution in the linked question.
Update
I've found the problem, the exception came from a 2nd field on the same form which indeed should have prompted it (because it was empty)... I was looking at an error which I thought came from trying to parse one string, when in fact it was from trying to parse another string... Sorry for wasting your time.
Original Question
I'm completely dumbfounded by this problem. I am basically running int.Parse("32") and it throws a FormatException. Here's the code in question:
private double BindGeo(string value)
{
Regex r = new Regex(#"\D*(?<deg>\d+)\D*(?<min>\d+)\D*(?<sec>\d+(\.\d*))");
Regex d = new Regex(#"(?<dir>[NSEW])");
var numbers = r.Match(value);
string degStr = numbers.Groups["deg"].ToString();
string minStr = numbers.Groups["min"].ToString();
string secStr = numbers.Groups["sec"].ToString();
Debug.Assert(degStr == "32");
var deg = int.Parse(degStr);
var min = int.Parse(minStr);
var sec = double.Parse(secStr);
var direction = d.Match(value).Groups["dir"].ToString();
var result = deg + (min / 60.0) + (sec / 3600.0);
if (direction == "S" || direction == "W") result = -result;
return result;
}
My input string is "32 19 17.25 N"
The above code runs on a .NET 4 web hosting service (aspspider) on an ASP.NET MVC 3 web application (with Razor as its view engine).
Note the assersion of degStr == "32" is valid! Also when I take the above code and run it in a console application it works just fine. I've scoured the web for an answer, nothing...
Any ideas?
UPDATE (stack trace)
[FormatException: Input string was not in a correct format.]
System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +9586043
System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +119
System.Int32.Parse(String s) +23
ParkIt.GeoModelBinder.BindGeo(String value) in C:\MyProjects\ParkIt\ParkIt\GeoBinder.cs:42
Line 42 is var deg = int.Parse(degStr); and note that the exception is in System.Int32.Parse (not in System.Double as was suggested).
You are wrongly thinking that it is the following line that is throwing the exception:
int.Parse("32")
This line is unlikely to ever throw an exception.
In fact it is the following line:
var sec = double.Parse(secStr);
In this case secStr = "17.25";.
The reason for that is that your hosting provider uses a different culture in which the . is not a decimal separator.
You have the possibility to specify the culture in your web.config file:
<globalization culture="en-US" uiCulture="en-US" />
If you don't do that, then auto is used. This means that the culture could be set based on the client browser preferences (which are sent with each request using the Accept-Language HTTP header).
Another possibility is to specify the culture when parsing:
var sec = double.Parse(secStr, CultureInfo.InvariantCulture);
This way you know for sure that . is the decimal separator for the invariant culture.
Testing this (via PowerShell):
PS [64] E:\dev #43> '32 19 17.25 N' -match "\D*(?\d+)\D*(?\d+)\D*(?\d+(\.\d*))"
True
PS [64] E:\dev #44> $Matches
Name Value
---- -----
sec 17.25
deg 32
min 19
1 .25
0 32 19 17.25
So the regex is working with all three named captures getting a value, all of which will parse OK (ie. it isn't something like \d matching something like U+0660: ARABIC-INDIC DIGIT ZERO that Int32.Parse doesn't handle).
But you do not check that the regex actually makes a match.
Therefore I suspect that the value passed to the function is not the input you expect. Put a breakpoint (or logging) at the start of the function and get the actual value of value.
I think what is happening is:
Value isn't what you think it is.
The regex fails to match.
The captures are empty
Int32.Parse("") is throwing (just confirmed: it throws a FormatException "Input string was not in a correct format.")
Adendum: Just noted you comment on the assertion.
If things seem contradictory go back to basics: at least one of your assumptions is wrong eg. there could be an off by one in the exception's line number (an edit to the file before going to that line number: very easy to do).
Stepping through with a debugger in this case is by far the easiest approach. On every expression check everything.
If you cannot use a debugger then try and remove that restriction, if not how about IntelliTrace? Othewrwise use some kind of logging (if you app doesn't have it, add it as you'll need it in the future for things like this).
try remove non unicode ( if any - non-visible) chars from string :
string s = "søme string";
s = Regex.Replace(s, #"[^\u0000-\u007F]", string.Empty);
edit
also - try to see its hex values to see where it is doing exceptio n :
BitConverter.ToString(buffer);
this will show you the hex values so you can verify...
also paste its value so we can see it.
It turns out that this is a non-question. The problem was that the exception came from a 2nd field on the same form which indeed should have prompted it (because it was empty)... I was looking at an error which I thought came from trying to parse one string, when in fact it was from trying to parse another string...
Sorry for wasting your time.
For example, say I wanted to determine whether this form was storing newlines as carriage returns or newlines or whatever characters. I'm often in situations where I'm writing code and am not sure what type of new-line character a file/form/whatever I'm parsing is using.
How could I determine this? Is there a way to determine this without actually doing a check inside of code? (It seems like I should be able to right-click and "show all characters" or something like that).
Note: I realize I could write code saying
(if == '\r') cout << "Carriage";
etc
but I have a feeling there's a simpler solution.
Maybe is list what you are looking for (from vim help):
:[range]l[ist] [count] [flags]
Same as :print, but display unprintable characters
with '^' and put $ after the line. This can be
changed with the 'listchars' option.
See ex-flags for [flags].
You can switch modes with:
:set list
and
:set nolist
Additionally you can use "listchars" as shown in this example:
You could for example check your document for occourences of "Carriage Return" or "New Line"/"Line Feed".
e.g. (php):
if( strstr( $yourstring , "\r" ) != false ){ // You have Carriage return
// Do something
}
elseif( strstr( $yourstring , "\n" ) != false ){ // You have New Line/Line feed
// Do something
}
else{
// You cannot determine which on is used, because the string is single-lined
}
I hope this is the thing you're looking for
Note: In windows "\r\n" is used to specify ne lines