Scato gramma breaf memo

• Scato gramma breaf memo
• Gramma
• Statements
• Groups
• Drawing and moving
• Affine transformations
• Colors
• Variables and calculations
• Conditions
• Loops
• Context
• Procedures
• Other

Gramma

Program is a sequence of wards (tokens). Words separate by spaces; spaces, tabulations and new-line-characters are all equal, and mean just space.

The first `#' in line and the rest of the line are ignored. It is comments.

Expressions (statements) are composed of tokens.

Statements

Groups

If you need to compose number of statements, you may user begin/end-block. It is one statement:

begin ...STATEMENTS... end

Drawing and moving

draw  VAR-OR-VAL VAR-OR-VAL
jump  VAR-OR-VAL VAR-OR-VAL
scale VAR-OR-VAL
right VAR-OR-VAL
left  VAR-OR-VAL
width VAR-OR-VAL

Affine transformations

affinescale  VAR-OR-VAL VAR-OR-VAL # Scale X and Y axis
affinerotate VAR-OR-VAL VAR-OR-VAL # Roatte X and Y axis
affinematrix VAR-OR-VAL VAR-OR-VAL VAR-OR-VAL VAR-OR-VAL # Specify matrix

Colors

color    VAR-OR-VAL VAR-OR-VAL VAR-OR-VAL            # red, green, blue
bgcolor  VAR-OR-VAL VAR-OR-VAL VAR-OR-VAL            # red, green, blue
mixcolor VAR-OR-VAL VAR-OR-VAL VAR-OR-VAL VAR-OR-VAL # red, green, blue, factor

Variables and calculations

Assignments:

set  VAR VAR-OR-VAL  # VAR := VAR-OR-VAL
sin  VAR VAR-OR-VAL  # VAR := sin(VAR-OR-VAL)
cos  VAR VAR-OR-VAL  # VAR := cos(VAR-OR-VAL)
exp  VAR VAR-OR-VAL  # VAR := exp(VAR-OR-VAL)
log  VAR VAR-OR-VAL  # VAR := log(VAR-OR-VAL)
sqrt VAR VAR-OR-VAL  # VAR := sqrt(VAR-OR-VAL)

Calculations:

add  VAR VAR-OR-VAL  # VAR := VAR + VAR-OR-VAL
sub  VAR VAR-OR-VAL  # VAR := VAR - VAR-OR-VAL
mul  VAR VAR-OR-VAL  # VAR := VAR * VAR-OR-VAL
div  VAR VAR-OR-VAL  # VAR := VAR / VAR-OR-VAL
mod  VAR VAR-OR-VAL  # VAR := VAR % VAR-OR-VAL
pow  VAR VAR-OR-VAL  # VAR := VAR ** VAR-OR-VAL

Changes:

incr VAR  # VAR := VAR + 1
decr VAR  # VAR := VAR - 1
neg  VAR  # VAR := - VAR
abs  VAR  # VAR := | VAR |

Conditions

if CONDITION then STATEMENT
if CONDITION then STATEMENT else STATEMENT

where CONDITION is a triplet:

VAR-OR-VAL OPERATION VAR-OR-VAL

and OPERATION is one of lt, gt, le, ge, eq or ne.

Loops

iterate VAR-OR-VAL STATEMENT
repeat STATEMENT until CONDITION
while CONDITION STATEMENT

Context

local     STATEMENT       # localize all aspects of context
save      STATEMENT       # localize variables values only
transform STATEMENT       # localize tortoise state only

Procedures

procedure NAME STATEMENT  # declare procedure
call      NAME            # call procedure by name

Other

nop  # do nothing