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Exercise: types

Write a PHP script based on the previous example that prints the value of $foo at each step

Modify the program so that it prints each line of code before dumping the variable value.

Generalise as a function executeWithTrace($prog, $var)

  • $prog is a text string, one program statement per line
  • $var is the name of the variable to be traced
  • scan program string, execute each line, dump variable