Using Arduino to execute commands from SD Card

Using Arduino Programming Questions
1

I'm looking to control WS2812b RGB Leds with an Arduino (with FastLED.h) but I want to be able to execute patterns from an SD Card instead of the program memory.

If I had a text file like so:

l0(255,255,255)l2(255,255,255)l4(255,255,255)l6(255,255,255)l8(255,255,255);
d1000;
l0(0,0,0)l2(0,0,0)l4(0,0,0)l6(0,0,0)l8(0,0,0)l1(255,255,255)l3(255,255,255)l5(255,255,255)l7(255,255,255)l9(255,255,255);
d1000;
l1(0,0,0)l3(0,0,0)l5(0,0,0)l7(0,0,0)l9(0,0,0);
d1000;

Where in "l#(#,#,#)" the first # represents the led place in the strip and the following #'s represent the R,G, and B values. "d#" represents a delay.

What necessary steps would I have to take to translate l3(255,0,255) to led[3].setRGB(255, 0, 255);

2

You can treat the SD file in a similar way to a Serial input. Look at examples #3 and #5 in Serial Input Basics

While a file may not look like a Serial input, it really is the same. The carriage-return-line-feed is used as the start and end characters.