Z.u.L. > Documentation > Context Help

# Descriptive Constructions

In this non-visual mode, there is an input line below the construction. The following differences apply.

- Choosing a tool will only display an input pattern.
- The necessary construction parameters must be supplied by name.
- The name of the constructed object may be given left of an equality sign =.
- The construction is carried out be pressing Return.

There is a fixed syntax for the input.

name=function(parameter,...)
name1,name2=function(parameter,...)

The second line applies to intersection and macros with several targets.

If the name is missing, the new object will get the default name.

Here is a short Description of the syntax. Note, that expressions may be used in all places, where a value is expected. Empty brackets can be omitted.

Syntax
Long
DEscription

A=P()
point
Generates a point at random position.

A=P(0,1)
A fixed point.

a=s(B,C)
segment
A segment from B to C.

a=s(B,2)
A segment of fixed length.

a=g(B,C)
line
A line through B and C.

a=r(B,C)
ray
A ray from B to C.

k=k(A,B)
circle
A circle around A trough B.

k=k(A,2)

k=k(A,B,C)
A circle around A with radius BC.

A=S(g,g)
intersection
An intersection between two lines.

A,B=S(k,k)
Both intersections between circles, or circles and lines.

away(A,P)
away
Keeps the intersection A away from the point P.

M=M(A,B)
middle
The midpoint of AB.

g=pl(g,A)
parallel
The parallel through A to g.

g=p(g,A)
plumb
The perpendicular through A to g.

a=w(A,B,C)
angle
The angle A,B,C

a=w(A,B,90)
An angle of fixed size.

A=area(P1,P2,P3)
area
Creates an area with these corners.

Creates a conic section through these points.

F=function(a,b,d,t,xt,yt)
Creates a function on [a,b] with step size d, plotting xt,yt,
which are expressions depending on the variable t.

value(P,0,1)
value
Fixes the coordinates of the point

value(s,2)
Fixes the length of the segment.

value(k,2)
Fixes the radius of a circle.

value(w,90)
Fixes the size of an angle.

value(true,o)
Sets the display of the value for o.

value(o)
Sets the display of the value for o to on.

value(true)
Sets the default display of values.

name(o,p)
name
Sets the name of o to p.

name(true,o)
Sets the display of the name for o.

name(o)
Sets the display of the name for o to on.

name(true)
Sets the default display of names.

hide(true,o)
hide
Hides or un-hides o.

hide(o)
Hides o.

hide(true)
Sets the default hidden state for objects.

col(green,o)
color
Sets the color of o to red, green, blue or brown.

col(green)
Sets the default color.

th(thick,o)
thickness
Sets the thickness of o to thick, normal or thin.

th(thick)
Sets the default thickness

type(square,P)
type
Sets the point type to square, circle, diamond or point.

type(square)
Sets the default point type.

part(k) part(true,k)
partial
Sets the object k to partial display or full display.

part(true)
Sets the default partial state.

fill(o) fill(true,o)
fill
Sets the object o to filled state or outline state.

back(o) back(true,o)
background
Sets the object o to the background or not.

window(0,0,5)
window
Sets the view window to width 2*5 and center (0,0).

valid(o) valid(true,o)
Treat segments and rays as lines in intersections and in
perpendicular lines. o is the intersection or the perpendicular.

obtuse(a) obtuse(true,a)
Set angles so that they can become greater then 180 degrees.

solid(a) solid(true,a)
Set the object to the nontransparent state.

restrict(c,A,B)
Restrict a circle to become an arc from A to B.

valid(o) valid(true,o)
Remove the restrictions from perpendicular lines and intersection.
These objects will be valid, even if the intersection is outside a
segment or an arc.

rename(A,B)
Rename the object A to B.

Macros can be used too. Names left of = will be assigned to targets. If there are several targets, the names must be separated by commas. One additional parameter may be used to assign a value for an object, which would be prompted in interactive mode.

Related topics: Syntax for Expressions, Running a Macro

Next topic: Descriptive constructions in files