1.5 Adding and Editing Expressions

New expressions are added to the workspace by entering them in the input area using the standard desktop keyboard or Myron's specialized Android keyboard. Expressions can also be added by touching them in this guide when it is displayed in the book reader. Once added, expressions can be moved around on the workspace display and removed from the workspace.

On a Windows desktop, Myron can make use of the Math Input Control to capture hand-drawn math expressions. This is particularly effective when running Myron on a Windows tablet. See §1.5.2 and §2.11.3.3.

There is often more than one expression in the workspace at the same time. One of these is called the active expression and is drawn in black. The others are inactive expressions and are drawn in gray. You can make any inactive expression into the active expression by touching or clicking on it.

The controls located to the right of the input and output areas (see Figures 1.1 and 1.2) aid the editing process and also display Myron expressions in other formats. They are described in §2.11.3.

To move an expression around on the workspace display,

• touch the expression repeatedly until the selection expands to include the entire expression;
• drag the expression to a new location.

After a while, it will become apparent that each expression has a “sweet spot” which will select the entire expression with one touch. (Hint: for an equation, the sweet spot is the = operator.)

At the bottom of the workspace display are two text areas and associated user-interface controls. The uppermost of these is the output area and contains the text version of the active expression. The lower one is the input area.

1.5.1 Input

In conjunction with the keyboard, the input area is where new expressions are composed. To enter an expression

• touch anywhere in the text-input area to display the keyboard
• click in the text-input area to prepare for keyboard input
• touch in the text-input area to clear the previous expression text; this also brings up the keyboard
• touch the bottom-right keyboard key when you have finished entering an expression; this replaces the active expression on the workspace display with the expression in the input area and also dismisses the keyboard
• touch or press enter; this replaces the active expression on the workspace display with the expression in the input area
• touch anywhere or click in the text-input area to reposition the cursor
• long-touch anywhere in the text-input area to bring up the selection and copy/paste controls
• drag to select; use standard control sequences to perform copy and paste: ctrl+x, ctrl+v, ctrl+c

1.5.2 Drawn Input

On Windows desktops and tablets, touch MIC to display Windows Math Input Control. Using the mouse or a touch-screen stylus, draw math expressions. Touch Insert to copy the drawn math expression to the algebra display. More detail on using the Math Input Control is given in §2.11.3.3.

1.5.3 Re-Input

Touch to replace the active expression with the expression in the input area; this will neither display nor dismiss the keyboard.

1.5.4 Add or Duplicate

To duplicate an expression on the workspace display

• touch the expression to make it active; this will also place a representation of the expression in the text-output area
• touch to copy the text-output area to the text-input area
• touch in the text-input area to create a new active expression

To add a new expression to the display

• touch the input area to bring up the keyboard
• before dismissing the keyboard, touch
• dismiss the keyboard

1.5.5 Duplicate part of an expression

To insert the selected subexpression in the text-input area.

• long touch the text-input area to bring up the text-selection cursors or to place the input cursor
• select a portion of text with the mouse
• replaces the selected input text with the subexpression or inserts it at the cursor location if no text is selected
• if keyboard is not visible, replaces the input text with the subexpression

1.5.6 Remove an expression

To remove an expression from the display,

• select the entire expression ;
• touch the delete item .

1.5.7 Select all

is used to select all the expressions on the workspace display. To indicate that all expressions have been selected, they are all displayed in black. After all expressions have been selected, one of several actions can be applied to all of them.

To clear the entire display,

• touch “select all” ;
• touch the delete item .

To move all the expressions,

• touch “select all” ;
• drag to a new location.

To plot all the expressions,

• touch “select all” ;
• Plot

1.5.8 Select some

Also called “multi-select”, this feature supports selection of more than one expression and more than one subexpression in an expression.

• select a subexpression using shift-click.
• select a subexpression and use Expressions Select .

An expression or subexpression that is already in the selection set can be removed by selecting it again.