Tag: language

Python AST: Evaluate an Expression

Do you want to convert a string of Python expression to Python object? Use ast $ cat myast.py import ast exDict = ‘{“name”: “1”}’ x = ast.literal_eval(exDict) print(x) $ python myast.py {‘name’: ‘1’} Another Example >>> import ast >>> x = u'[ “A”,”B”,”C” , ” D”]’ >>> x = ast.literal_eval(x) >>> x [‘A’, ‘B’, ‘C’,…

Understanding Ruby Symbols

Ruby is an interpreted language. It is dynamically typed and uses a new memory for a variable. A variable has a name and a value. Symbols are an optimized variable that holds single instance of memory. It is good for variables that assume the same values across the program such as hash table keys. h…

Golang: Switch-case does not fall through!

Unlike C/C++ switch-case statements, Golang switch case does not fall through. package main import ( “fmt” ) func main() { fmt.Print(“Go runs on “) os := “darwin” switch os { case “darwin”: case “linux”: fmt.Println(“Linux.”) default: // freebsd, openbsd, // plan9, windows… fmt.Printf(“%s.\n”, os) } } The above code does not print anything! package main…

Forward declaration of a structure in C

What do you think of following code? /* * decl.h */ struct junk { int a; }; ———————————————- /* * fwd.c * We have not included the header file decl.h. */ #include struct junk; int main() { struct junk *ptr; printf(“%d”, ptr->a); } You will get compilation error that structure object ptr is incomplete. This…