/* Demo of macsyma substitution macros. */

EVAL_WHEN([TRANSLATE,BATCH,DEMO],
          IF GET('SHAREM,'VERSION) = FALSE
             THEN LOADFILE(AUTOLO,FASL,DSK,SHAREM))$

/* define a macro to compute a numerical integration. 
   We want it to take an expression, a variable, and upper and
   lower limits. The expression will be evaluated for values
   of the variable between the upper and lower limits. */

RECT_RULE('EXP,'X,A,B,DX)=>
 (MODEDECLARE([A,B,DX],FLOAT),
  BLOCK([%_SUM:0.0],MODEDECLARE(%_SUM,FLOAT),
        FOR X:A THRU B STEP DX DO %_SUM:%_SUM+EXP,
	DX*%_SUM))$

GRIND(RECT_RULE);

DEFINE(G(A),MACROEXPAND(RECT_RULE(X^2,X,0.0,A,0.1)))$
GRIND(G);