Data commit

Task/Function-composition/BBC-BASIC/function-composition.basic

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+      REM Create some functions for testing:
+      DEF FNsqr(a) = SQR(a)
+      DEF FNabs(a) = ABS(a)
+
+      REM Create the function composition:
+      SqrAbs = FNcompose(FNsqr(), FNabs())
+
+      REM Test calling the composition:
+      x = -2 : PRINT ; x, FN(SqrAbs)(x)
+      END
+
+      DEF FNcompose(RETURN f%, RETURN g%)
+      LOCAL f$, p% : DIM p% 7 : p%!0 = f% : p%!4 = g%
+      f$ = "(x)=" + CHR$&A4 + "(&" + STR$~p% + ")(" + \
+      \             CHR$&A4 + "(&" + STR$~(p%+4) + ")(x))"
+      DIM p% LEN(f$) + 4 : $(p%+4) = f$ : !p% = p%+4
+      = p%