spindrake

Experiments in using Bison/Flex for Spin parsing

Design Goals

• Fewer operators
  • Replaced operators
    • ^^x -> sqrt(x)
    • ||x -> abs(x)
    • x #> y -> max(x, y)
    • x <# y -> min(x, y)
    • ?x -> rand(x)
    • =< -> <=
    • => -> >=
  • Removed operators
    • =>=
    • =<=
    • <=
    • >=
    • <>=
    • ===
    • and=
    • or=
    • **
    • **=
    • x?
    • |<
    • >|
    • +x
  • Removed keywords
    • constant
    • string
• Single address operator: @
• Automatic constant folding
• Automatic string termination (no string() keyword)
• address[0] -> address
• Unused code removal
• Subdirectory support
• Dedicated ASM block for assembly

Specification

Operators

From highest precedence to lowest:

1. Unary: --, ++, ~, ~~, @
2. Unary: -, !
3. Shift: <<, >>, ~>, <-, ->, ><
4. Bitwise and: &
5. Bitwise or: |, ^
6. Multiplicative: *, /, //
7. Additive: +, -
8. Relational: ==, <>, <, >, <=, =>
9. Boolean not: not
10. Boolean and: and
11. Boolean or: or
12. Assignment: :=, +=, -=, *=, /=, //=, <<=, >>=, ~>=, ->=, <-=, ><=, &=, |=, ^=