A-M baby

Task/Arithmetic-evaluation/Julia/arithmetic-evaluation.julia

@@ -0,0 +1,41 @@
+julia> expr="2 * (3 -1) + 2 * 5"
+"2 * (3 -1) + 2 * 5"
+
+julia> parsed = parse(expr) #Julia provides low-level access to language parser for AST/Expr creation
+:(+(*(2,-(3,1)),*(2,5)))
+
+julia> t = typeof(parsed)
+Expr
+
+julia> names(t) #shows type fields
+(:head,:args,:typ)
+
+julia> parsed.args #Inspect our 'Expr' type innards
+3-element Any Array:
+ :+
+ :(*(2,-(3,1)))
+ :(*(2,5))
+
+julia> typeof(parsed.args[2]) #'Expr' types can nest
+Expr
+
+julia> parsed.args[2].args
+3-element Any Array:
+  :*
+ 2
+  :(-(3,1))
+
+julia> parsed.args[2].args[3].args #Will nest until lowest level of AST
+3-element Any Array:
+  :-
+ 3
+ 1
+
+julia> eval(parsed)
+14
+
+julia> eval(parse("1 - 5 * 2 / 20 + 1"))
+1.5
+
+julia> eval(parse("2 * (3 + ((5) / (7 - 11)))"))
+3.5