5 Programming

Here is a short introductory example to the Asymptote programming language that highlights the similarity of its control structures with those of C and C++.

// This is a comment.

// Declaration: Declare x to be a real variable;
real x;

// Assignment: Assign the real variable x the value 1.
x=1.0;

// Conditional: Test if x equals 1 or not.
if(x == 1.0) {
  write("x equals 1.0");
} else {
  write("x is not equal to 1.0");
}

// Loop: iterate 10 times
for(int i=0; i < 10; ++i) {
  write(i);
}

Loops, together with user-defined functions, are illustrated in the files wheel.asy and cube.asy in the animations subdirectory of the examples directory. These examples use the gifmerge command to merge multiple images into a gif animation, using the ImageMagick convert program.

Asymptote also supports while, do, break, and continue statements just as in C/C++. In addition, it supports many features beyond the ones found in those languages.

• Data types: void, bool, int, real, pair, triple, string
• Guides and paths: Specifying lines and curves
• Pens: Colors, line types, line widths, font sizes
• Transforms: Affine transforms
• Frames and pictures: Canvases for immediate and deferred drawing
• Files: Reading and writing your data
• Structures: Organize your data
• Operators: Arithmetic and logical operators
• Implicit scaling: Avoiding those ugly *s
• Functions: Traditional and high-order functions
• Arrays: Dynamic vectors
• Casts: Implicit and explicit casts
• Import: Importing external Asymptote packages
• Static: Where to allocate your variable?