paragraphs.hpp

Go to the documentation of this file.

//==================================================================================================
/// \file
/// This header file is part of sub-namespace #alib::lang::format of module \alib_basecamp of
/// the \aliblong.
///
/// \emoji :copyright: 2013-2024 A-Worx GmbH, Germany.
/// Published under \ref mainpage_license "Boost Software License".
//==================================================================================================
#ifndef HPP_ALIB_LANG_FORMAT_PARAGRAPHS
#define HPP_ALIB_LANG_FORMAT_PARAGRAPHS 1
#pragma once
#include "alib/lang/format/formatterpythonstyle.hpp"
#include "alib/monomem/aliases/astringma.hpp"
#include "alib/monomem/aliases/stddeque.hpp"
#include "alib/monomem/aliases/stdvector.hpp"
#include <stack>
 
namespace alib {  namespace results { class Exception; }
namespace lang::format {
//==================================================================================================
/// This class is used to format textual output, like console output.
///
/// One central \b static method is #Format, which formats a "paragraph" that starts at a
/// certain index of the managed \b %AString buffer and reaches to its end.
///
/// When an instance of the class is created, the members of the class provide the text
/// buffer as well as the other parameters which are needed for the static method. With methods
/// #Add, member #Formatter is used to append the given parameters and then the new paragraph is
/// formatted using the static method #Format.<br>
/// This way, a longer text might be built by repetitive calls.
//==================================================================================================
class Paragraphs
{
    // #############################################################################################
    // Fields
    // #############################################################################################
  protected:
    /// Allocator used for internal container types.
    MonoAllocator           allocator;
 
    /// Internal buffer, used for field #Paragraphs, if no external string object was given.
    AString                 text;
 
  public:
    /// A reference to the text buffer. Either refers to otherwise protected field #text or to
    /// what was given in alternative construction.
    AString&                Buffer;
 
    /// The formatter to use.
    /// In the constructor, this shared pointer is initialized with the
    /// - \alib{lang::format;Formatter::Default;ALib Default Formatter},
    ///   in the case that this object's template character type equals \ref alib::character, or
    /// - A shared pointer to a newly created formatter object of a corresponding character type
    ///   otherwise.
    SPFormatter                 Formatter;
 
    /// Used as parameter \p{lineWidth} of static method invocations.
    integer                     LineWidth                                                       = 0;
 
    /// Used as parameter \p{justifyChar} of static method invocations.
    /// Usually set to <c>' '</c> to enable paragraph width justification.<br>
    /// Defaults to <c>'\\0'</c> which disables it.
    character                   JustifyChar                                                  = '\0';
 
    /// Used to detect special commands given with format strings.
    /// \see Method #AddMarked for more information.
    ///
    /// Defaults to <c>'@'</c>.
    character                   MarkerChar                                                    = '@';
 
    /// The bullet used with increasing bullet depths.
    /// Defaults to <c>'*'</c>, <c>'-'</c>, <c>'*'</c>, <c>'-'</c>, <c>'*'</c>, <c>'-'</c>.
    StdVectorMono<character>    MarkerBullets;
 
    /// Used as parameter \p{indent} of static method invocations.<br>
    /// The indent string of the first line.
    ///
    /// This field can either be manipulated by direct access or preferably with
    /// overloaded methods #PushIndent and #PopIndent.
    AStringMA                   IndentFirstLine;
 
    /// Used as parameter \p{indent} of static method invocations.<br>
    /// The indent string of text lines, excluding the first line.
    ///
    /// This field can either be manipulated by direct access or preferably with
    /// overloaded methods #PushIndent and #PopIndent.
    AStringMA                   IndentOtherLines;
 
    /// The stack of indent substring sizes in string #IndentFirstLine.
    /// Used with #PushIndent and #PopIndent.
    std::stack<integer, StdDequeMono<integer>>  IndentSizesFirstLine;
 
    /// The stack of indent substring sizes in string #IndentOtherLines.
    /// Used with #PushIndent and #PopIndent.
    std::stack<integer, StdDequeMono<integer>>  IndentSizesOtherLines;
 
    /// This field is increased whenever a line of text added is longer than its current
    /// value.
    /// Might be used by to detect the maximum line width when field #LineWidth is set to \c 0
    /// and hence no auto wrap is done.
    integer                     DetectedMaxLineWidth                                             =0;
 
 
  protected:
    /// Internally reused list of boxes.
    BoxesMA                     boxes;
 
    /// Buffer for processing marked text.
    AString                     markedBuffer;
 
    /// Buffer for processing marked text.
    size_t                      markerBulletLevel                                                =0;
 
    // #############################################################################################
    // Constructor/Destructor
    // #############################################################################################
  public:
    /// Parameterless constructor.
    /// Internal buffer #text will be used with reference #Buffer.
    /// For field #Formatter, \alib{lang::format;Formatter::Default} will be used.
    ALIB_API                 Paragraphs();
 
    /// Alternative constructor that accepts an external buffer to use.
    /// @param externalBuffer The external buffer to use and fill.
    ALIB_API                 Paragraphs( AString& externalBuffer );
 
    // #############################################################################################
    // Interface
    // #############################################################################################
  public:
    //==============================================================================================
    /// Formats one or more paragraphs (separated by \b NewLine symbols) with three optional
    /// features:
    ///
    /// - Wrapping of lines longer than lineWidth (word wrap)
    /// - Justify the text, which here means "full justification", i.e., format the text to have
    ///   lines of the exact same width.
    /// - Adding an indentation to each line with an optionally different indentation for the
    ///   first line after a \b NewLine symbol and subsequent ones.
    ///
    /// The paragraph starts at \p{startIdx} and all of the rest of the string is treated
    /// as one paragraph. New-line character sequences found within the paragraph are considered
    /// manual line ends. Hence, no block formatting for lines ending with a new line character
    /// is performed.
    ///
    /// The method is static and hence can be used with arbitrary buffers.
    /// Non-static methods #Add invoke this method after adding the given content
    /// to the internal buffer. Furthermore, convenience functions and corresponding member
    /// variables, simplify the use of this method, when indirectly used through an instance of
    /// the class.
    ///
    /// @param text              The text containing the paragraph to format.
    /// @param startIdx          The start of the paragraph.
    /// @param lineWidth         The width of the line. If \c 0 or negative, no line wrap is
    ///                          performed.
    /// @param justifyChar       If this is unequal to <c>'\0'</c> it denotes the fill
    ///                          character used to justify the paragraph.
    ///                          Defaults to <c>'\0'</c>, which disables justification.
    /// @param[out] maxLineWidth Provides the maximum width of all text lines written.
    /// @param indentFirstLine   The indent string of the first line. Defaults to \c nullptr.
    /// @param indentOtherLines  The indent string of subsequent lines. Defaults to \c nullptr.
    //==============================================================================================
    ALIB_API
    static
    void    Format( AString&      text,
                    integer       startIdx,
                    integer       lineWidth,
                    character     justifyChar,
                    integer&      maxLineWidth,
                    const String& indentFirstLine = nullptr,
                    const String& indentOtherLines= nullptr  );
 
    //==============================================================================================
    /// Appends the given objects \p{args} to the internal #Buffer with the help of member
    /// #Formatter. Then, static method #Format is invoked, providing our public
    /// members as parameters. Finally, a newline sequence is added to #Buffer, but only if the
    /// buffer is not empty and if it does not already end with a newline sequence.
    ///
    /// @throws <b>alib::lang::format::FMTExceptions</b><br>
    ///         Rethrows exceptions from the formatter caused by errors in provided \p{args}.
    ///
    /// @param args   The list of arguments to add.
    //==============================================================================================
    template<typename TAllocatorArgs>
    void    Add( boxing::TBoxes<TAllocatorArgs>&  args );
 
    //==============================================================================================
    /// Variadic template argument version of #Add.
    ///
    /// @param args   The variadic list of arguments to add.
    /// @return A reference to ourselves to allow concatenated calls.
    //==============================================================================================
    template <typename... BoxedObjects>
    Paragraphs&  Add( const BoxedObjects&... args )
    {
        boxes.clear();
        boxes.Add( args... );
        Add( boxes );
        return *this;
    }
 
    //==============================================================================================
    /// This method implements a pre-processing of the text before #Add paragraphs found in
    /// the text.
    ///
    /// The pre-processing is quite simple. Its purpose is to allow longer strings (e.g., loaded
    /// from a resource pool) with multiple paragraphs to be formatted by embedded escape
    /// sequences to include indents and nested bullet schemes.
    ///
    /// The escape sequences begin with the character stored in field #MarkerChar, which defaults
    /// to <c>'@'</c>. The following table documents the sequences:
    ///
    /// Sequence | Description
    /// ---------|------------------------------------------------------------------------
    /// \@@   | Inserts the marker character itself.
    /// \@>>  | Indent text by two spaces
    /// \@<<  | Un-indent text by two spaces
    /// \@*>  | Increases bullet level.
    /// \@<*  | Decreases bullet level
    /// \@P   | Inserts a new line (like '\n') but without ending the current and starting a new bullet point.
    /// \@HLc | Inserts a horizontal line of width #LineWidth using \p{c} as fill character.
    ///
    /// The nested bullet point characters are received from vector #MarkerBullets.
    ///
    /// @throws <b>alib::lang::format::FMTExceptions</b>
    ///   - \alib{lang::format::FMTExceptions;UnknownMarker}
    ///   - \alib{lang::format::FMTExceptions;EndmarkerWithoutStart}
    ///   - Rethrows formatter exceptions occurring due to errors in provided \p{args}.
    ///
    /// @param args       The list of arguments to add.
    //==============================================================================================
    template<typename TAllocatorArgs>
    void            AddMarked( boxing::TBoxes<TAllocatorArgs>&  args );
 
    //==============================================================================================
    /// Variadic template argument version of #AddMarked.
    ///
    /// @throws <b>alib::lang::format::FMTExceptions</b>
    ///   - \alib{lang::format::FMTExceptions;UnknownMarker}
    ///   - \alib{lang::format::FMTExceptions;EndmarkerWithoutStart}
    ///
    /// @param args   The variadic list of arguments to add.
    /// @return A reference to ourselves to allow concatenated calls.
    //==============================================================================================
    template <typename... BoxedObjects>
    Paragraphs&     AddMarked( const BoxedObjects&... args )
    {
        boxes.clear();
        boxes.Add( args... );
        AddMarked( boxes );
        return *this;
    }
 
    //==============================================================================================
    /// Removes the last new line character at the end of the #Buffer.
    ///
    /// @return A reference to the text object.
    //==============================================================================================
    AString&        RemoveLastNewLine()
    {
        if( Buffer.EndsWith( NEW_LINE ) )
            Buffer.template DeleteEnd<NC>( NEW_LINE.Length() );
        return Buffer;
    }
 
    //==============================================================================================
    /// Clears field #Buffer.
    ///
    /// @return A reference to ourselves to allow concatenated calls.
    //==============================================================================================
    ALIB_API
    Paragraphs&     Clear();
 
 
    //==============================================================================================
    /// Add a given number of characters (default is spaces) to the indentation strings
    /// #IndentFirstLine and #IndentOtherLines.
    ///
    /// Use #PopIndent to remove the indent.
    ///
    /// @param qty       The quantity of characters to add or remove
    /// @param fillChar  The character (used only if \p{qty} is positive).
    /// @return A reference to ourselves to allow concatenated calls.
    //==============================================================================================
    ALIB_API
    Paragraphs&     PushIndent( uinteger qty, character fillChar = ' ' );
 
    //==============================================================================================
    /// Add the given strings to members #IndentFirstLine and #IndentOtherLines.
    ///
    /// @param indentFirstLine   The string to add to the current indentation stored in
    ///                          #IndentFirstLine.
    /// @param indentOtherLines  The string to add to the current indentation stored in
    ///                          #IndentOtherLines.<br>
    ///                          Defaults to \b NULL_STRING, which sets it to the same value as
    ///                          \p{indentFirstLine}.
    /// @return A reference to ourselves to allow concatenated calls.
    //==============================================================================================
    ALIB_API
    Paragraphs&     PushIndent( const String& indentFirstLine,
                           const String& indentOtherLines=nullptr);
 
    //==============================================================================================
    /// Removes the most recently added indent.
    /// @return A reference to ourselves to allow concatenated calls.
    //==============================================================================================
    ALIB_API
    Paragraphs&     PopIndent();
}; // class Paragraphs
 
#if !DOXYGEN
template<> ALIB_API  void    Paragraphs::Add      ( boxing::TBoxes<HeapAllocator>&  args );
template<> ALIB_API  void    Paragraphs::Add      ( boxing::TBoxes<MonoAllocator>&  args );
template<> ALIB_API  void    Paragraphs::Add      ( boxing::TBoxes<PoolAllocator>&  args );
template<> ALIB_API  void    Paragraphs::AddMarked( boxing::TBoxes<HeapAllocator>&  args );
template<> ALIB_API  void    Paragraphs::AddMarked( boxing::TBoxes<MonoAllocator>&  args );
template<> ALIB_API  void    Paragraphs::AddMarked( boxing::TBoxes<PoolAllocator>&  args );
#endif // !DOXYGEN
}} // namespace [alib::lang::format]
 
#endif // HPP_ALIB_LANG_FORMAT_PARAGRAPHS