class

Reply::ExpressionEditor

Inherits Reference < Object

The ExpressionEditor allows to edit and display an expression.

Its main task is to provide the display of the prompt and a multiline expression within the term bounds, and ensure the correspondence between the cursor on screen and the cursor on the expression.

Usage example:

# new editor:
@editor = ExpressionEditor.new(
  prompt: ->(expr_line_number : Int32) { "prompt>" }
)

# edit some code:
@editor.update do
  @editor << %(puts "World")

  insert_new_line(indent: 1)
  @editor << %(puts "!")
end

# move cursor:
@editor.move_cursor_up
4.times { @editor.move_cursor_left }

# edit:
@editor.update do
  @editor << "Hello "
end

@editor.end_editing

@editor.expression # => %(puts "Hello World"\n  puts "!")
puts "=> ok"

# clear and restart edition:
@editor.prompt_next

The above displays:

prompt>puts "Hello World"
prompt>  puts "!"
=> ok
prompt>

Methods that modify the expression should be placed inside an update so the screen can be refreshed taking in account the adding or removing of lines, and doesn't boilerplate the display.

Constructors

new

Creates a new ExpressionEditor with the given prompt.

Class methods

parts_from_colorized(line, width, prompt_size = 0)

Splits the given line (colorized) into parts delimited by wrapping.

Because line is colorized, it's hard to know when it's wrap based on its size (colors sequence might appear anywhere in the string) Here we does the following:

Create a String::Builder for the first part (part_builder)
Iterate over the line, parsing the color sequence
Count cursor x for each char unless color sequences
If count goes over term width: reset x to 0, and create a new String::Builder for next part.

Instance methods

<<(char : Char) : self

Should be called inside an update.

If char is \n or \r, inserts a new line with indent 0. Does nothing if the char is an ascii_control?.

<<(str : String) : self

Should be called inside an update.

back

Should be called inside an update.

clear_expression

Should be called inside an update.

color=(color : Bool)

color?

current_line

current_line=(line)

Should be called inside an update.

current_word

Returns the word under the cursor following word_delimiters.

current_word=(replacement)

Replaces the word under the cursor by replacement, then moves cursor at the end of replacement. Should be called inside an update.

current_word_begin_end

Returns begin and end position of current_word.

cursor_on_last_line?

delete

Should be called inside an update.

delete_after_cursor

Should be called inside an update.

delete_before_cursor

Should be called inside an update.

delete_line(y)

Should be called inside an update.

delete_word

Should be called inside an update.

empty?

end_editing(replacement : Array(String) | Nil = nil)

Prints the full expression (without view bounds), and eventually replace it by replacement.

expression

expression_before_cursor(x = @x, y = @y)

expression_height

height

The editor height, if not set (nil), equal to term height.

height=(height : Int32 | Nil)

The editor height, if not set (nil), equal to term height.

insert_new_line(indent)

Should be called inside an update.

lines

move_cursor_down(allow_scrolling = true)

move_cursor_left(allow_scrolling = true)

move_cursor_right(allow_scrolling = true)

move_cursor_to(x, y, allow_scrolling = true)

move_cursor_to_begin(allow_scrolling = true)

move_cursor_to_end(allow_scrolling = true)

move_cursor_to_end_of_line(y = @y, allow_scrolling = true)

move_cursor_up(allow_scrolling = true)

move_word_backward

move_word_forward

next_line=(line)

Should be called inside an update.

next_line?

output

output=(output : IO)

previous_line=(line)

Should be called inside an update.

previous_line?

prompt_next

Clears the expression and start a new prompt on a next line.

replace(lines : Array(String))

scroll_down

scroll_up

set_header

Sets a Proc allowing to display a header above the prompt. (used by auto-completion)

io: The IO in which the header should be displayed. previous_height: Previous header height, useful to keep a header size constant. Should returns the exact height printed in the io.

set_highlight

Sets the Proc to highlight the expression.

update(force_full_view = false, &)

Refresh the screen.

It clears the display of the current expression, then yields for modifications, and displays the new expression.

if force_full_view is true, whole expression is displayed, even if it overflow the term width, otherwise the expression is bound and can be scrolled.

update(force_full_view = false)

width

The editor width, if not set (nil), equal to term width.

width=(width : Int32 | Nil)

The editor width, if not set (nil), equal to term width.

word_back

Should be called inside an update.

word_delimiters

The list of characters delimiting words.

default: \n\t+-*/,;@&%<>"'^\\[](){}|.~:=!?

word_delimiters=(word_delimiters : Array(Char))

The list of characters delimiting words.

default: \n\t+-*/,;@&%<>"'^\\[](){}|.~:=!?

x

Tracks the cursor position relatively to the expression's lines, (y=0 corresponds to the first line and x=0 the first char) This position is independent of text wrapping so its position will not match to real cursor on screen.

| : cursor position

prompt>def very_looo
ooo|ng_name            <= wrapping
prompt>  bar
prompt>end

For example here the cursor position is x=16, y=0, but real cursor is at x=3,y=1 from the beginning of expression.

y