CommandLine.Text.TextWrapper Class Reference

A utility class to word-wrap and indent blocks of text. More...

Public Member Functions
	TextWrapper (string input)
TextWrapper	WordWrap (int columnWidth)
	Splits a string into a words and performs wrapping while also preserving line-breaks and sub-indentation.
TextWrapper	Indent (int numberOfSpaces)
	Indent all lines in the TextWrapper by the desired number of spaces.
string	ToText ()
	Returns the current state of the TextWrapper as a string.

Static Public Member Functions
static string	WrapAndIndentText (string input, int indentLevel, int columnWidth)
	Convenience method to wraps and indent a string in a single operation.

Private Member Functions
string[]	WordWrapLine (string line, int columnWidth)

Static Private Member Functions
static List< StringBuilder >	AddWordToLastLineOrCreateNewLineIfNecessary (List< StringBuilder > lines, string word, int columnWidth)
	When presented with a word, either append to the last line in the list or start a new line.
static string	RightString (string str, int n)
	Return the right part of a string in a way that compensates for Substring's deficiencies.
static string	LeftString (string str, int n)
	Return the left part of a string in a way that compensates for Substring's deficiencies.

Private Attributes
string[]	lines

Detailed Description

A utility class to word-wrap and indent blocks of text.

Definition at line 13 of file TextWrapper.cs.

Constructor & Destructor Documentation

TextWrapper()

CommandLine.Text.TextWrapper.TextWrapper

(

string

input

)

Definition at line 17 of file TextWrapper.cs.

        {
            //start by splitting at newlines and then reinserting the newline as a separate word
            //Note that on the input side, we can't assume the line-break style at run time so we have to
            //be able to handle both.  We can't use Environment.NewLine because that changes at
            //_runtime_ and may not match the line-break style that was compiled in
            lines = input
                    .Replace("\r", "")
                    .Split(new[] { '\n' },
                           StringSplitOptions.None
                          );
        }

Member Function Documentation

AddWordToLastLineOrCreateNewLineIfNecessary()

static List< StringBuilder > CommandLine.Text.TextWrapper.AddWordToLastLineOrCreateNewLineIfNecessary ( List< StringBuilder >  lines, string  word, int  columnWidth  )

staticprivate

When presented with a word, either append to the last line in the list or start a new line.

Parameters

lines	A list of StringBuilders containing results so far
word	The individual word to append
columnWidth	The usable text space

The 'word' can actually be an empty string. It's important to keep these - empty strings allow us to preserve indentation and extra spaces within a line.

Returns

The same list as is passed in

Definition at line 134 of file TextWrapper.cs.

        {
            //The current indentation level is based on the previous line but we need to be careful
            string previousLine = lines.LastOrDefault()
                                       ?.ToString() ??
                                  string.Empty;
 
            bool wouldWrap = !lines.Any() || (word.Length > 0 && previousLine.Length + word.Length > columnWidth);
 
            if (!wouldWrap)
            {
                //The usual case is we just append the 'word' and a space to the current line
                //Note that trailing spaces will get removed later when we turn the line list 
                //into a single string
                lines.Last()
                     .Append(word + ' ');
            }
            else
            {
                //The 'while' here is to take account of the possibility of someone providing a word
                //which just can't fit in the current column.  In that case we just split it at the 
                //column end.
                //That's a rare case though - most of the time we'll succeed in a single pass without
                //having to split
                //Note that we always do at least one pass even if the 'word' is empty in order to 
                //honour sub-indentation and extra spaces within strings
                do
                {
                    int availableCharacters = Math.Min(columnWidth, word.Length);
                    string segmentToAdd = LeftString(word, availableCharacters) + ' ';
                    lines.Add(new StringBuilder(segmentToAdd));
                    word = RightString(word, availableCharacters);
                }
                while (word.Length > 0);
            }
 
            return lines;
        }

Indent()

TextWrapper CommandLine.Text.TextWrapper.Indent

(

int

numberOfSpaces

)

Indent all lines in the TextWrapper by the desired number of spaces.

Parameters

numberOfSpaces

The number of spaces to indent by

Returns

this

Definition at line 63 of file TextWrapper.cs.

        {
            lines = lines
                    .Select(line => numberOfSpaces.Spaces() + line)
                    .ToArray();
 
            return this;
        }

LeftString()

static string CommandLine.Text.TextWrapper.LeftString ( string  str, int  n  )

staticprivate

Return the left part of a string in a way that compensates for Substring's deficiencies.

Definition at line 190 of file TextWrapper.cs.

        {
            return n >= str.Length || str.Length == 0
                       ? str
                       : str.Substring(0, n);
        }

RightString()

static string CommandLine.Text.TextWrapper.RightString ( string  str, int  n  )

staticprivate

Return the right part of a string in a way that compensates for Substring's deficiencies.

Definition at line 180 of file TextWrapper.cs.

        {
            return n >= str.Length || str.Length == 0
                       ? string.Empty
                       : str.Substring(n);
        }

ToText()

string CommandLine.Text.TextWrapper.ToText

(

)

Returns the current state of the TextWrapper as a string.

Returns

Definition at line 76 of file TextWrapper.cs.

        {
            //return the whole thing as a single string
            return string.Join(Environment.NewLine, lines);
        }

WordWrap()

TextWrapper CommandLine.Text.TextWrapper.WordWrap

(

int

columnWidth

)

Splits a string into a words and performs wrapping while also preserving line-breaks and sub-indentation.

Parameters

columnWidth

The number of characters we can use for text

This method attempts to wrap text without breaking words For example, if columnWidth is 10 , the input "a string for wrapping 01234567890123" would return "a string "for "wrapping "0123456789 "0123"

Returns

this

Definition at line 46 of file TextWrapper.cs.

        {
            //ensure we always use at least 1 column even if the client has told us there's no space available
            columnWidth = Math.Max(1, columnWidth);
 
            lines = lines
                    .SelectMany(line => WordWrapLine(line, columnWidth))
                    .ToArray();
 
            return this;
        }

WordWrapLine()

string[] CommandLine.Text.TextWrapper.WordWrapLine ( string  line, int  columnWidth  )

private

Definition at line 102 of file TextWrapper.cs.

        {
            //create a list of individual lines generated from the supplied line
 
            //When handling sub-indentation we must always reserve at least one column for text!
            string unindentedLine = line.TrimStart();
            int currentIndentLevel = Math.Min(line.Length - unindentedLine.Length, columnWidth - 1);
            columnWidth -= currentIndentLevel;
 
            return unindentedLine.Split(' ')
                                 .Aggregate(new List<StringBuilder>(),
                                            (lineList, word) =>
                                                AddWordToLastLineOrCreateNewLineIfNecessary(lineList, word, columnWidth)
                                           )
                                 .Select(builder => currentIndentLevel.Spaces() +
                                                    builder.ToString()
                                                           .TrimEnd()
                                        )
                                 .ToArray();
        }

WrapAndIndentText()

static string CommandLine.Text.TextWrapper.WrapAndIndentText ( string  input, int  indentLevel, int  columnWidth  )

static

Convenience method to wraps and indent a string in a single operation.

Parameters

input	The string to operate on
indentLevel	The number of spaces to indent by
columnWidth	The width of the column used for wrapping

The string is wrapped then indented so the columnWidth is the width of the usable text block, and does NOT include the indentLevel.

Returns

the processed string

Definition at line 93 of file TextWrapper.cs.

        {
            return new TextWrapper(input)
                   .WordWrap(columnWidth)
                   .Indent(indentLevel)
                   .ToText();
        }

Member Data Documentation

lines

string [] CommandLine.Text.TextWrapper.lines

private

Definition at line 15 of file TextWrapper.cs.

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The documentation for this class was generated from the following file:

• deps/commandlineparser/src/CommandLine/Text/TextWrapper.cs