Modelica.Utilities.Streams

Read from files and write to files

Information


Library content

Package Streams contains functions to input and output strings to a message window or on files. Note that a string is interpreted and displayed as html text (e.g., with print(..) or error(..)) if it is enclosed with the Modelica html quotation, e.g.,

string = "<html> first line <br> second line </html>".

It is a quality of implementation, whether (a) all tags of html are supported or only a subset, (b) how html tags are interpreted if the output device does not allow to display formatted text.

In the table below an example call to every function is given:

Function/typeDescription
print(string)
print(string,fileName)
Print string "string" or vector of strings to message window or on file "fileName".
stringVector = readFile(fileName) Read complete text file and return it as a vector of strings.
(string, endOfFile) = readLine(fileName, lineNumber) Returns from the file the content of line lineNumber.
lines = countLines(fileName) Returns the number of lines in a file.
error(string) Print error message "string" to message window and cancel all actions
close(fileName) Close file if it is still open. Ignore call if file is already closed or does not exist.

Use functions scanXXX from package Strings to parse a string.

If Real, Integer or Boolean values shall be printed or used in an error message, they have to be first converted to strings with the builtin operator String(...). Example:

  if x < 0 or x > 1 then
     Streams.error("x (= " + String(x) + ") has to be in the range 0 .. 1");
  end if;

Extends from Modelica.Icons.Library (Icon for library).

Package Content

NameDescription
Modelica.Utilities.Streams.print print Print string to terminal or file
Modelica.Utilities.Streams.readFile readFile Read content of a file and return it in a vector of strings
Modelica.Utilities.Streams.readLine readLine Reads a line of text from a file and returns it in a string
Modelica.Utilities.Streams.countLines countLines Returns the number of lines in a file
Modelica.Utilities.Streams.error error Print error message and cancel all actions
Modelica.Utilities.Streams.close close Close file


Modelica.Utilities.Streams.print Modelica.Utilities.Streams.print

Print string to terminal or file

Information


Syntax

Streams.print(string);
Streams.print(string,fileName);

Description

Function print(..) opens automatically the given file, if it is not yet open. If the file does not exist, it is created. If the file does exist, the given string is appended to the file. If this is not desired, call "Files.remove(fileName)" before calling print ("remove(..)" is silent, if the file does not exist). The Modelica environment may close the file whenever appropriate. This can be enforced by calling Streams.close(fileName). After every call of "print(..)" a "new line" is printed automatically.

Example

  Streams.print("x = " + String(x));
  Streams.print("y = " + String(y));
  Streams.print("x = " + String(y), "mytestfile.txt");

See also

Streams, Streams.error, String

Extends from Modelica.Icons.Function (Icon for a function).

Inputs

TypeNameDefaultDescription
Stringstring""String to be printed
StringfileName""File where to print (empty string is the terminal)

Modelica definition

function print "Print string to terminal or file"
  extends Modelica.Icons.Function;
  input String string="" "String to be printed";
  input String fileName="" "File where to print (empty string is the terminal)";
external "C" ModelicaInternal_print(string, fileName);
end print;

Modelica.Utilities.Streams.readFile Modelica.Utilities.Streams.readFile

Read content of a file and return it in a vector of strings

Information


Syntax

stringVector = Streams.readFile(fileName)

Description

Function readFile(..) opens the given file, reads the complete content, closes the file and returns the content as a vector of strings. Lines are separated by LF or CR-LF; the returned strings do not contain the line separators.

Extends from Modelica.Icons.Function (Icon for a function).

Inputs

TypeNameDefaultDescription
StringfileName Name of the file that shall be read

Outputs

TypeNameDescription
StringstringVector[countLines(fileName)]Content of file

Modelica definition

function readFile 
  "Read content of a file and return it in a vector of strings"
  extends Modelica.Icons.Function;
  input String fileName "Name of the file that shall be read";
  output String stringVector[countLines(fileName)] "Content of file";

algorithm 
  for i in  1:size(stringVector, 1) loop
    stringVector[i] := readLine(fileName, i);
  end for;
  Streams.close(fileName);
end readFile;

Modelica.Utilities.Streams.readLine Modelica.Utilities.Streams.readLine

Reads a line of text from a file and returns it in a string

Information


Syntax

(string, endOfFile) = Streams.readLine(fileName, lineNumber)

Description

Function readLine(..) opens the given file, reads enough of the content to get the requested line, and returns the line as a string. Lines are separated by LF or CR-LF; the returned string does not contain the line separator. The file might remain open after the call.

If lineNumber > countLines(fileName), an empty string is returned and endOfFile=true. Otherwise endOfFile=false.

Extends from Modelica.Icons.Function (Icon for a function).

Inputs

TypeNameDefaultDescription
StringfileName Name of the file that shall be read
IntegerlineNumber Number of line to read

Outputs

TypeNameDescription
StringstringLine of text
BooleanendOfFileIf true, end-of-file was reached when trying to read line

Modelica definition

function readLine 
  "Reads a line of text from a file and returns it in a string"
  extends Modelica.Icons.Function;
  input String fileName "Name of the file that shall be read";
  input Integer lineNumber(min=1) "Number of line to read";
  output String string "Line of text";
  output Boolean endOfFile 
    "If true, end-of-file was reached when trying to read line";
 external "C" string = ModelicaInternal_readLine(fileName,lineNumber,endOfFile);
end readLine;

Modelica.Utilities.Streams.countLines Modelica.Utilities.Streams.countLines

Returns the number of lines in a file

Information


Syntax

numberOfLines = Streams.countLines(fileName)

Description

Function countLines(..) opens the given file, reads the complete content, closes the file and returns the number of lines. Lines are separated by LF or CR-LF.

Extends from Modelica.Icons.Function (Icon for a function).

Inputs

TypeNameDefaultDescription
StringfileName Name of the file that shall be read

Outputs

TypeNameDescription
IntegernumberOfLinesNumber of lines in file

Modelica definition

function countLines "Returns the number of lines in a file"
  extends Modelica.Icons.Function;
  input String fileName "Name of the file that shall be read";

  output Integer numberOfLines "Number of lines in file";
external "C" numberOfLines = ModelicaInternal_countLines(fileName);
end countLines;

Modelica.Utilities.Streams.error Modelica.Utilities.Streams.error

Print error message and cancel all actions

Information


Syntax

Streams.error(string);

Description

Print the string "string" as error message and cancel all actions. Line breaks are characterized by "\n" in the string.

Example

  Streams.error("x (= " + String(x) + ")\nhas to be in the range 0 .. 1");

See also

Streams, Streams.print, String

Extends from Modelica.Icons.Function (Icon for a function).

Inputs

TypeNameDefaultDescription
Stringstring String to be printed to error message window

Modelica definition

function error "Print error message and cancel all actions"
  extends Modelica.Icons.Function;
  input String string "String to be printed to error message window";
  external "C" ModelicaError(string);
end error;

Modelica.Utilities.Streams.close Modelica.Utilities.Streams.close

Close file

Information


Syntax

Streams.close(fileName)

Description

Close file if it is open. Ignore call if file is already closed or does not exist.

Extends from Modelica.Icons.Function (Icon for a function).

Inputs

TypeNameDefaultDescription
StringfileName Name of the file that shall be closed

Modelica definition

function close "Close file"
  extends Modelica.Icons.Function;
  input String fileName "Name of the file that shall be closed";
  external "C" ModelicaStreams_closeFile(fileName);
end close;

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