Class 30: A Sample Pascal Parser

Held: Monday, 12 April 2004

Summary: Today we pause for breath and consider a sample Pascal parser.

Related Pages:

• EBoard.
• Sample Code.

Notes:

• My parser is almost ready to go. 1 point extra credit to your group for finding errors after 4:15 today. Limit of 3 points per group.
• Today is a chance to go over parsing and type-checking issues.

Overview:

• Some problems in parsing Pascal.
• Some solutions.
• Notes on type checking.

Parsing Difficulties

• What difficulties did you encounter in writing your parsers?
• The harder parts for me were:
  • Some problems remembering differences from Stupid.
  • Assignment statements vs. procedure calls.
  • Function calls vs. variables.
  • Variables
• We'll look at how I solved these and other issues.

Type Checking

• We'll look at some general strategies, if there's time.