Type and Symbol checking

[at15]

• Symbol checking
  • recover from duplicate declaration
    • replace with new symbol 9210937
  • recover from undefined identifier
    • use rhs type and put it into symbol table f97ab95
• Type checking
  • declare 9210937
  • assign f97ab95
  • resolve? operator?
    • a34feb6
• Recovery principle
  • log recovery in trace f7e6f32
  • if incompatible happens when declare or assign, we choose to keep the original type instead of the type in rhs
    • int a = "s", a is still int
    • int a = 1; a = "s", a is still int
  • if undefined identifier happen for assign, we use the type of rhs
    • a = 1, a is int, this is actually type induction ...
• String support 02dfa0e

[at15]

will go back to this issue after built in function is introduced, the error handling and recovery things are still unclear