Parsers. Transforming text into an HTML table

In the process of website development web developers often face a problem of correct transformation of text into HTML tables. In this article the specialists of WebStudio2U will share their experience of coding a simple text parser. We will tell you how to write a simple application using Delphi programming language in 15 minutes. This application will transform a text with delimiters into an HTML table. This article is intended for the users who have minimal knowledge of Delphi.

First of all let us place two Memo (mmo1 and mmo2) components and one Button (btn1) component into the form. Now let us proceed to editing the values of the component parameters using the Object Inspector panel. You should set the ScrollBars parameter of TMemo class components to ssBoth and edit the value of the Lines parameter – erase the name of the component from the text. Then change the value of the Caption parameter for the button into “Create a table” (see image 1).

Image 1

Click the btn1 twice and replace the procedure by the procedure given below:

procedure TForm1.btn1Click(Sender: TObject); var i,j,mx,fw,ftd:Integer; s,title:String; ar:TArray; begin mx:=0; //Reset the MX variable which will contain the information about the maximum number of table columns fw:=0; //A variable used to store information on whether the table title was rendered or not mmo2.Lines.BeginUpdate; //Stop line-by-line updating of the text field of the mmo2 component mmo2.Clear; //Clear mmo 2 text field for i:=0 to mmo1.Lines.Count-1 do // … the lines of the source text in the loop. Determine the maximum number of the table columns. begin ar:=explode(Char(9), mmo1.Lines.Strings[i],0);//Divide the line of the source code into sublines (enter the lines into the ar array). In this case the tabulation character – Char(9) – serves as a delimiter if (Length(mmo1.Lines.Strings[i])>0) and (i=0) then title:=ar[0]; //If the length of a line is more than 0 and it is the first line store the Table title into the title variable if mx<Length(ar) then mx:= Length(ar); //If the maximum is smaller than the number of lines in the ar array assign a new value to the mx variable end; mmo2.Lines.Add('<h2 class="li4">'+title+'</h2>');//Output the table title mmo2.Lines.Add('<center><table border="0" cellspacing="2" cellpadding="2" summary="'+title+'" width="100%">');//Insert the HTML code of the table mmo2.Lines.Add('<tbody>'); //Start the output of the body of the HTML table for i:=0 to mmo1.Lines.Count-1 do //… the lines of the source text in the loop. begin if ((title<>'') and (i=0)) then //If the title of the table has been output omit the first line begin end else begin ar:=explode(Char(9), mmo1.Lines.Strings[i],0);//Divide the line of the source code into sublines (enter the lines into the ar array). In this case the tabulation character – Char(9) – serves as a delimiter ftd:=0;//Remove the variable that outputs additional information into certain columns s:='<tr>';//Start the line of the HTML table for j:=0 to mx-1 do //A loop where thanks to the mx variable the elements will be output irrespective of the number of elements in the ar array begin if (j>Length(ar)-1) then //Verification of the number of elements in the ar array and the number of the current element s:=s+'<td> </td>' //If the number of the current element is more than the number of elements in the ar array output a blank cell else begin if (Trim(ar[j])='') then s:=s+'<td> </td>' else //If the current element of the ar array is a blank line output a blank cell of the HTML table begin if fw=0 then s:=s+'<td width="47%">'+trim(ar[j])+'</td>' else //Set the width of the first cell of the table (47%) if (ftd=0) or (ftd=2) then s:=s+'<td class="col1">'+trim(ar[j])+'</td>' else //If there is data for the cells 1 and 3 output the cells with formatting s:=s+'<td>'+trim(ar[j])+'</td>'; //If all previous conditions are not fulfilled just output the current element of the ar array. Inc(fw);//Increase the fw variable by 1 (cell counter) Inc(ftd);//Increase the ftd variable by 1 (column counter) end; end; end; mmo2.Lines.Add(s+'</tr>'); //Close the line of the HTML table end; end; SetLength(ar,0); //Zero the lines array mmo2.Lines.Add('</tbody>');//Close the body of the HTML table mmo2.Lines.Add('</table></center>');//Close the HTML table mmo2.Lines.EndUpdate;//Engage the update of the text field end;

To make this code work you should add the function which will divide the line into the line array with the delimiter. You should insert the code of the function above the code of the procedure that processes the click on the button.

function explode(cDelimiter, sValue : string; iCount : integer) : TArray; //The following parameters are transmitted to the function: cDelimiter – delimiting symbol, sValue – line that should be divided into sublines, iCound – array limiter (0 – no limit). var s : string; i,p : integer; begin s := sValue; i := 0; while length(s) > 0 do begin inc(i); SetLength(result, i); p := pos(cDelimiter,s); if ( p > 0 ) and ( ( i < iCount ) OR ( iCount = 0) ) then begin result[i - 1] := copy(s,0,p-1); s := copy(s,p + length(cDelimiter),length(s)); end else begin result[i - 1] := s; s:= ''; end; end; end;

That's all! Now you can compile the program (F9).

It is presumed that the source text will be placed into mmo1, and after the processing the HTML table will be output into mmo2.

To make it more convenient we have also added an optional handler for Ctrl+A combination press on the mmo2 component (onKeyDown event).

procedure CopyStringToClipboard(const Value: String);//Procedure that copies the Cyrillic text into the clipboard correctly const RusLocale = (SUBLANG_DEFAULT shl $A) or LANG_RUSSIAN; var hMem: THandle; pData: Pointer; begin Clipboard.Open; try Clipboard.AsText := Value; hMem := GlobalAlloc(GMEM_MOVEABLE, SizeOf(DWORD)); try pData := GlobalLock(hMem); try DWORD(pData^) := LANG_UKRAINIAN; finally GlobalUnlock(hMem); end; Clipboard.SetAsHandle(CF_LOCALE, hMem); finally GlobalFree(hMem); end; finally Clipboard.Close; end; end;

The handler for the onKeyDown event of the mmo2 component itself

if((Key=Ord('A')) and (ssCtrl in Shift)) then // begin mmo2.SelectAll; //Select all text of the HTML table CopyStringToClipboard(mmo2.Text);//Copy the text to clipboard end;

Such a simple but very useful application may be useful, for example, if you need to transform the keywords statistics provided by the search engines into an HTML table. First you should copy the data to Excel or other similar program via the clipboard, prepare the information there, then paste it into mmo1 (when the text is copied to Excel it is automatically transformed into the text with a delimiter – tabulation character) and transform it into an HTML table with the help of the program.

If you have any questions, contact us – we will be glad to answer!

P.S. To make the procedure of copying to clipboard work you will need to add the Clipbrd module into the list of connected modules (uses list in the very beginning of the program code).

TAGS
parser, html table, text to table, delphi, text with delimiters, code, program, application, text parser