Add docs for the calc command (#1290)

docs/commands/calc.md

@@ -0,0 +1,116 @@
+# calc
+
+calc is a command that takes a math expression from the pipeline and calculates that into a number.
+
+This command supports the following operations - 
+
+operations :
+* binary operators: +, -, *, /, % (remainder), ^ (power)
+* unary operators: +, -, ! (factorial)
+
+functions :
+* sqrt, abs
+* exp, ln, log10
+* sin, cos, tan, asin, acos, atan, atan2
+* sinh, cosh, tanh, asinh, acosh, atanh
+* floor, ceil, round
+* signum
+* max(x, ...), min(x, ...): maximum and minimumum of 1 or more numbers
+
+constants:
+* pi
+* e
+ 
+## Examples - 
+
+```
+> echo "1+2+3" | calc
+6.000000000000000
+> echo "1-2+3" | calc
+2.000000000000000
+> echo "-(-23)" | calc
+23.00000000000000
+> echo "5^2" | calc
+25.00000000000000
+> echo "5^3" | calc
+125.0000000000000
+> echo "min(5,4,3,2,1,0,-100,45)" | calc
+-100.0000000000000
+> echo "max(5,4,3,2,1,0,-100,45)" | calc
+45.00000000000000
+> echo "sqrt(2) | calc"
+1.414213562373095
+> echo pi | calc
+3.141592653589793
+> echo e | calc
+2.718281828459045
+> echo "sin(pi / 2)" | calc
+1.000000000000000
+> echo "floor(5999/1000)" | calc
+5.000000000000000
+```
+
+```
+❯ open abc.json
+───┬──────
+ # │ size 
+───┼──────
+ 0 │  816 
+ 1 │ 1627 
+ 2 │ 1436 
+ 3 │ 1573 
+ 4 │  935 
+ 5 │   52 
+ 6 │  999 
+ 7 │ 1639 
+───┴──────
+
+❯ open abc.json | format "({size} + 500) * 4"
+───┬──────────────────
+ # │ <value> 
+───┼──────────────────
+ 0 │ (816 + 500) * 4 
+ 1 │ (1627 + 500) * 4 
+ 2 │ (1436 + 500) * 4 
+ 3 │ (1573 + 500) * 4 
+ 4 │ (935 + 500) * 4 
+ 5 │ (52 + 500) * 4 
+ 6 │ (999 + 500) * 4 
+ 7 │ (1639 + 500) * 4 
+───┴──────────────────
+
+❯ open abc.json | format "({size} + 500) * 4" | calc
+───┬───────────
+ # │ <value> 
+───┼───────────
+ 0 │ 5264.0000 
+ 1 │ 8508.0000 
+ 2 │ 7744.0000 
+ 3 │ 8292.0000 
+ 4 │ 5740.0000 
+ 5 │ 2208.0000 
+ 6 │ 5996.0000 
+ 7 │ 8556.0000 
+───┴───────────
+
+❯ open abc.json | format "({size} - 1000) * 4" | calc
+───┬────────────
+ # │ <value> 
+───┼────────────
+ 0 │  -736.0000 
+ 1 │  2508.0000 
+ 2 │  1744.0000 
+ 3 │  2292.0000 
+ 4 │  -260.0000 
+ 5 │ -3792.0000 
+ 6 │    -4.0000 
+ 7 │  2556.0000 
+───┴────────────
+```
+
+Note that since `calc` uses floating-point numbers, the result may not always be precise. 
+
+```
+> echo "floor(5999999999999999999/1000000000000000000)" | calc
+6.000000000000000
+```