Contour Interpreter

Introduction

This is a interpreter for the Contour project. It parses a basic function syntax for spreadsheets so that operations on tags can be performed.

Language Examples

Variable Declarations & Assignments

• Variables can be assigned with arithmetical/boolean operators and expressions and also tag expressions to link to other cells on other sheets.
• For an integer "num" with value 7:

  let num = 7

• For a string "name" with value "Alice":

 let name = "alice"

• For a variable "cellVal" that links to the spreadsheet cell referenced as #(row, col) + 7

let cellVal = #(row, col) + 7

Conditional Statements :

• Multiline for clear understanding

• Can use boolean operators to link statements.

• If statements can nest

• For an if statement to see if the a string variable "name" is equal to "alice" and if so then set variable "correctName" to true and if not then set name to the value of cell (2, name) :

   if (name = "alice")
   then let correctName = true
   else then let name = #(2, name)
  

• Another example if statement. Notice how & and 'and' can be used in the exact same way and will produce the same result. The return keyword returns the result of the function :

    if (name = "alice" & age = 22)
   then return 1
   else if (name = "bob" and age = 23)
   then return 2
   else then return 0
  

If there are any errors in the function code then it is output to the user, giving the type of error and the location of it also.