Expecco Code Snippets/en - Versionsgeschichte

Cg: /* Working with Code */

2025-05-20T12:20:39Z

Working with Code

← Nächstältere Version		Version vom 20. Mai 2025, 12:20 Uhr
Zeile 2:		Zeile 2:
	Before going into concrete details, you should learn to use the tools MethodFinder, Workspace and SystemBrowser.		Before going into concrete details, you should learn to use the tools MethodFinder, Workspace and SystemBrowser.

	The MethodFinder lets you find methods (i.e. virtual functions) by entering arguments and a desired result.		The [[How_to_Program/en#MethodFinder:_Find_Functions_by_Example\|MethodFinder]] lets you find methods (i.e. virtual functions) by entering arguments and a desired result.
	For example, to convert 'abc' into 'ABC' the MethodFinder wil tell you that the function named "asUppercase" will do that.		For example, to convert 'abc' into 'ABC' the MethodFinder wil tell you that the function named "asUppercase" will do that.

Zeile 8:		Zeile 8:

	Finally, a SystemBrowser shows the concrete implementation (i.e. the source code) of the underlying system functions. If you use the menu function "Implementors", you can search for the "asUppercase" function and see its implementation(s). Most functions also provide examples near the bottom of the source code, which can be selected and executed pretty much like in a Workspace.		Finally, a SystemBrowser shows the concrete implementation (i.e. the source code) of the underlying system functions. If you use the menu function "Implementors", you can search for the "asUppercase" function and see its implementation(s). Most functions also provide examples near the bottom of the source code, which can be selected and executed pretty much like in a Workspace.


	== Code Snippets for Common Tasks ==		== Code Snippets for Common Tasks ==

Cg: /* Parsing */

2025-02-17T08:28:30Z

Parsing

← Nächstältere Version		Version vom 17. Februar 2025, 08:28 Uhr
Zeile 663:		Zeile 663:
	domNode attributes		domNode attributes
	domNode children		domNode children
	enumerate the children (all of them, ~~recusrive~~):		enumerate the children (all of them, recursive):
	domNode allChildrenDo: [:eachChild \| ... ]		domNode allChildrenDo: [:eachChild \| ... ]

Cg: /* Parsing */

2025-02-17T08:28:14Z

Parsing

← Nächstältere Version		Version vom 17. Februar 2025, 08:28 Uhr
Zeile 696:		Zeile 696:
	domNode attributes		domNode attributes
	domNode children		domNode children
	enumerate the children (all of them, ~~recusrive~~):		enumerate the children (all of them, recursive):
	domNode allChildrenDo: [:eachChild \| ... ]		domNode allChildrenDo: [:eachChild \| ... ]

Cg am 17. Februar 2025 um 08:27 Uhr

2025-02-17T08:27:29Z

← Nächstältere Version		Version vom 17. Februar 2025, 08:27 Uhr
Zeile 1:		Zeile 1:
			== Working with Code ==
			Before going into concrete details, you should learn to use the tools MethodFinder, Workspace and SystemBrowser.

			The MethodFinder lets you find methods (i.e. virtual functions) by entering arguments and a desired result.
			For example, to convert 'abc' into 'ABC' the MethodFinder wil tell you that the function named "asUppercase" will do that.

			A Workspace lets you enter a piece of code and execute it, for example, entering the text " 'abc' asUppercase ", selectingthat piece of code and using the menu function "printIt" will execute the code and paste the result at the cursor position.

			Finally, a SystemBrowser shows the concrete implementation (i.e. the source code) of the underlying system functions. If you use the menu function "Implementors", you can search for the "asUppercase" function and see its implementation(s). Most functions also provide examples near the bottom of the source code, which can be selected and executed pretty much like in a Workspace.


	== Code Snippets for Common Tasks ==		== Code Snippets for Common Tasks ==

Cg: /* String Processing */

2025-02-14T14:25:22Z

String Processing

← Nächstältere Version		Version vom 14. Februar 2025, 14:25 Uhr
Zeile 328:		Zeile 328:
	'%d %02x' scanf: '1234 AF' "/ C-scanf like reading (returns an array)		'%d %02x' scanf: '1234 AF' "/ C-scanf like reading (returns an array)

	== String Processing ==

	=== Comparing Strings containing Numbers (String to Numberverctor) ===		=== Comparing Strings containing Numbers (String to Numberverctor) ===

Cg: /* Converting Numbers to Strings and Vice Versa */

2025-02-14T14:24:22Z

Converting Numbers to Strings and Vice Versa

← Nächstältere Version		Version vom 14. Februar 2025, 14:24 Uhr
Zeile 327:		Zeile 327:

	'%d %02x' scanf: '1234 AF' "/ C-scanf like reading (returns an array)		'%d %02x' scanf: '1234 AF' "/ C-scanf like reading (returns an array)

			== String Processing ==

			=== Comparing Strings containing Numbers (String to Numberverctor) ===

			Given two strings ("string1" and "string2") which contain numbers in ascii:

			string1 := '-150.00, 27.18, 2.50, 60.20, 112.82, 19.00'.
			string2 := '-150, 27.18, 2.5, 60.2, 112.82, 19'.

			Use "=" to see if strings or collections are different:
			string1 = string2 ifTrue:[
			...
			] ifFalse:[
			...
			].

			The above has the disadvantage, that it requires the two strings to be exactly the same,
			including the same number of spaces in between numbers and also the same number of decimal digits.

			In general, a more intelligent algorithm is needed:
			- split each string into a collection of substrings, separated by (in this case) comma characters
			- convert each such substring into a number
			- compare the two collections which now contain numbers

			==== Subproblem1: splitting a longer string into parts ====
			To split a string into a collection of substrings (separated by commas):
			string splitBy: $,

			or assuming that more than one separator character is to be handled:
			string splitByAny: ',;'

			==== Subproblem2: reading a number from a string ====
			To convert a string to a number:
			string asNumber

			Notice, that this will convert the string '19' into an integer and '19.0' into a float.
			This is usually not a problem, as the integer 19 will compare equal against the float 19.0 as true.

			==== Getting a collection of numbers ====
			Thus, to convert one string into an array of numbers,
			first split, then collect the results from converting each:
			subStrings1 := string1 splitBy: $, .
			numbers1 := subStrings1 collect:[:eachPart \| eachPart asNumber ].
			or, in one line:
			( string1 splitBy: $, ) collect:[:eachPart \| eachPart asNumber ].

			Then compare the collections (each now containing numbers).

			==== Solution ====
			So the final solution to our problem is:

			numbers1 := ( string1 splitBy: $, ) collect:[:eachPart \| eachPart asNumber ].
			numbers2 := ( string2 splitBy: $, ) collect:[:eachPart \| eachPart asNumber ].
			numbers1 = numbers2 ifFalse:[
			...
			] ifTrue:[
			...
			].

			==== Comparing the size of the two number vectors ====

			You might want to check for the same number of values:
			numbers1 size = nubers2 size ifFalse:[ ... ].

			==== Alternative (if the number of values is fix) ====

			If your lines all have the same fix number of values, you can also use scanf, as in:

			numbers1 := '%f, %f, %f, %f, %f, %f' scanf:string1.
			numbers2 := '%f, %f, %f, %f, %f, %f' scanf:string2.

			numbers1 = numbers2 ifTrue:[
			...
			].

			==== Finding the first difference between 2 vectors ====

			To find the first different value:
			index := numbers1 with:numbers2 findFirst:[:nr1 :nr2 \| nr1 ~= nr2].
			index = 0 ifTrue:[
			... "all equal"
			] ifFalse:[
			... "first different at index"
			]

			==== Finding the longest common prefix of 2 vectors ====
			samePrefix := numbers1 commonPrefixWith: numbers2

			==== Alternative using Streams ====

			We can also open streams on each string and read numbers pairwise.
			The following code is somewhat longer:
			- verifies that the numbers are readable (i.e. no invalid stuff in the string)
			- provides the index of the first different value

			indexOfFirstDifference := nil.
			sameNumberOfValues := true.
			stream1 := string1 readStream.
			stream2 := string2 readStream.
			runIndex := 1.
			[:break \|
			[stream1 atEnd] whileFalse:[
			\|nr1 nr2\|

			stream2 atEnd ifTrue:[
			sameNumberOfValues := false.
			break value.
			].
			nr1 := Number readFrom:stream1 onError:[ self error:'invalid nr in stream1' ].
			nr2 := Number readFrom:stream2 onError:[ self error:'invalid nr in stream2' ].
			nr1 = nr2 ifFalse:[
			indexOfFirstDifference := runIndex.
			break value.
			].
			runIndex := runIndex + 1.
			stream1 skipThrough:$,.
			stream2 skipThrough:$,.
			].
			sameNumberOfValues := stream2 atEnd.
			] valueWithExit.
			sameNumberOfValues ifFalse:[
			... "not same number of values"
			] ifTrue:[
			indexOfFirstDifference isNil ifFalse:[
			... "different value detected"
			] ifTrue:[
			... "ok"
			]
			]

	=== String/Text Processing ===		=== String/Text Processing ===

Cg: /* Input and Output Pins */

2022-02-17T12:19:21Z

Input and Output Pins

← Nächstältere Version		Version vom 17. Februar 2022, 12:19 Uhr
Zeile 15:		Zeile 15:
	\|x\|		\|x\|
	x := ''inPinName'' value.		x := ''inPinName'' value.
	JavaScript and NodeJS:		JavaScript and [[Expecco_API/en#Pin_Functions_.28NodeJS.29\|NodeJS]]:
	var x;		var x;
	x = ''inPinName''.value();		x = ''inPinName''.value();

Cg: /* Parsing */

2022-02-06T15:25:22Z

Parsing

← Nächstältere Version		Version vom 6. Februar 2022, 15:25 Uhr
Zeile 550:		Zeile 550:
	parse an XML string, to get a DOM (Document Object Model) node:		parse an XML string, to get a DOM (Document Object Model) node:
	domNode := XML::XMLParser parse:''aString''		domNode := XML::XMLParser parse:''aString''
			parse an XML file, to get a DOM node (in expecco 22.1):
			domNode := XML::XMLParser parseFile: aFilename
	ask a node for its tag, attributes or children:		ask a node for its tag, attributes or children:
	domNode tag		domNode tag

Cg: /* Input and Output Pins */

2022-02-06T15:21:54Z

Input and Output Pins

← Nächstältere Version		Version vom 6. Februar 2022, 15:21 Uhr
Zeile 24:		Zeile 24:
	x = ''inPinName''.value()		x = ''inPinName''.value()
	[[Expecco_API/en#Pin_Functions_.28C.29\|C]]:		[[Expecco_API/en#Pin_Functions_.28C.29\|C]]:
	long l = longValue(''inPinName'')		long l = longValue(''inPinName'');
	char* s = stringValue(''inPinName'')		char* s = stringValue(''inPinName'');
	float f = floatValue(''inPinName'')		float f = floatValue(''inPinName'');
	double d = doubleValue(''inPinName'')		double d = doubleValue(''inPinName'');
	unsigned char* b = bytesValue(''inPinName'')		unsigned char* b = bytesValue(''inPinName'');

	To write a value ''x'' to an output pin named ''outPinName'', use:		To write a value ''x'' to an output pin named ''outPinName'', use:
	<br>Smalltalk:		<br>Smalltalk:
	''outPinName'' value: ''x''		''outPinName'' value: ''x''.
	JavaScript and ~~NodeJS~~:		JavaScript, NodeJS and Groovy:
	''outPinName''.value(''x'');		''outPinName''.value(''x'');
	Python:		Python:
	''outPinName''.value(''x'')		''outPinName''.value(''x'')
	C:		C:
	putLong(''outPinName'', l) // l has long or int type		putLong(''outPinName'', l); // l has long or int type
	putString(''outPinName'', s) // s has char* type (0-terminated)		putString(''outPinName'', s); // s has char* type (0-terminated)
	putStringN(''outPinName'', s, n) // s has char* type (n chars sent to pin)		putStringN(''outPinName'', s, n); // s has char* type (n chars sent to pin)
	putFloat(''outPinName'', f)		putFloat(''outPinName'', f);
	putDouble(''outPinName'', d)		putDouble(''outPinName'', d);
	putBytesN(''outPinName'',b, n) // n bytes sent to pin		putBytesN(''outPinName'',b, n); // n bytes sent to pin

	=== Bits & Bytes ===		=== Bits & Bytes ===

Cg: /* Input and Output Pins */

2022-02-06T15:15:33Z

Input and Output Pins

← Nächstältere Version		Version vom 6. Februar 2022, 15:15 Uhr
Zeile 17:		Zeile 17:
	JavaScript and NodeJS:		JavaScript and NodeJS:
	var x;		var x;
	x = ''inPinName''.value().		x = ''inPinName''.value();
			[[Expecco_API/en#Pin_Functions_.28Groovy.29\|Java/Groovy]]:
	Python:
			Object x;
			x = ''inPinName''.value();
			[[Expecco_API/en#Pin_Functions_.28Python.29\|Python]]:
	x = ''inPinName''.value()		x = ''inPinName''.value()
			[[Expecco_API/en#Pin_Functions_.28C.29\|C]]:
	C:
	long l = longValue(''inPinName'')		long l = longValue(''inPinName'')
	char* s = stringValue(''inPinName'')		char* s = stringValue(''inPinName'')