Use square brackets for parenthesis in newton

newton/newton

@@ -80,14 +80,15 @@ getConfiguredClient()
 validateExpression()
 {
   local parsedExpression
-  parsedExpression=$(echo $1 | grep -Eo "[0-9 + -- / * ^ . a-z A-Z ~ :]*")
-  if [[ "$parsedExpression" != "$1" ]];then { echo "Error: Expression contains invalid characters"; return 1; }; fi
+  originalExpression=$(echo $1 | sed "s/\[/\(/g" | sed "s/\]/\)/g")
+  parsedExpression=$(echo $1 | sed "s/\[/\(/g" | sed "s/\]/\)/g" | grep -Eo "[0-9 + -- / * ^ . a-z A-Z ~ : ( ) ]*")
+  if [[ "$parsedExpression" != "$originalExpression" ]];then { echo "Error: Expression contains invalid characters"; return 1; }; fi
 }
 
 encodeEquation()
 {
   originalEquation=$1
-  equation=$(echo $originalEquation | sed "s:/:(over):g" | sed "s/~/|/g" | sed "s/-/%2D/g")
+  equation=$(echo $originalEquation | sed "s:\[:\(:g" | sed "s:\]:\):g"  | sed "s:/:(over):g" | sed "s/~/|/g" | sed "s/-/%2D/g")
 }
 
 validateOperation()
@@ -112,7 +113,7 @@ printAnswer()
   cat <<EOF
 ================================
 |Operation: $operation
-|Expression: $originalEquation
+|Expression: $originalExpression
 |Result: $result
 ================================
 EOF
@@ -130,7 +131,7 @@ Usage: newton [operation] [expression] or newton [flag]
  ===================================================
 |Operations     Sample Expression      Sample Result|
 |---------------------------------------------------|
-|Simplify           2^2+2(2)                 8      |
+|Simplify       [[2x^2]+7]*[4x^2]    8 x^4 + 28 x^2 |
 |Factor             x^2 + 2x             x (x + 2)  |
 |Derive              x^2+2x               2 x + 2   |
 |Integrate           x^2+2x         1/3 x^3 + x^2 +C|
@@ -146,6 +147,16 @@ Usage: newton [operation] [expression] or newton [flag]
 |Abs                   -2                    2      |
 |Log                   2~8                   3      | (Log base 2 of eight)
  ===================================================
+Valid Symbols:
+  + add
+  - subtract
+  [ left parenthesis (you must use brackets bash has a bultin for parenthesis)
+  ] right parenthesis (you must use brackets bash has a bultin for parenthesis)
+  * multiply
+  / divide
+  ^ power
+  : between the range of left and right side (only for area under curve)
+  ~ parmeter on right side (only for area, tangent line and log)
 EOF
 }