-- Written by Gabriel Dos Reis (gdr AT cs DOT tamu DOT edu)
-- Last modified on Jan 15, 2007.
--
-- This file contains a low-level code for parsing
-- a Spad source file into an internal AST.  The
-- AST, for the entire file, is presented as a list of
-- toplevel statements (mostly definitions).
-- Since this is low-level code, I don't expect people
-- to get here, and you cannot directly use it.  If you think, 
-- you need to get to here, then something is already wrong.
-- There is a higher-level interface, written in SPAD, to this
-- code.  See gdr-spad-parser.spad.
--
-- To use this file:
--    (1) translate it to Common Lisp, with bootsys:
--         bootsys -batch -eval '(boottran::boottoclc "gdr-reader.boot")'
--
--    (2) compile gdr-spad-parser.spad
--
--


gdrParseSpadFile sourceFile ==
  $SPAD : local := true                        -- we are parsing Spad, 
  $BOOT : local := false                       --   not Boot.

  OUT_-STREAM := _*STANDARD_-OUTPUT_*          -- spit any noise to
                                               -- the standard output
  -- we need to tell the post-parsing transformers that we're compiling;
  -- few parse forms have slightly different representations
  -- depending on whether we are in interpreter mode or compiler mode.
  savedInteractiveMode := $InteractiveMode
  $InteractiveMode := false
  oldParserAutoloadOnceTrigger()               -- load parsing functions
  oldCompilerAutoloadOnceTrigger()
  INIT_-BOOT_/SPAD_-READER()
  savedInStream := IN_-STREAM                  -- we need to restore the
                                               -- global input stream state
                                               -- after we finished messing
                                               -- with it
  IN_-STREAM := MAKE_-INSTREAM sourceFile
  INITIALIZE_-PREPARSE IN_-STREAM
  asts := []                                   -- accumulates parse trees
                                               -- for all definitions in 
                                               -- sourceFile.
  while ^(_*EOF_* or FILE_-CLOSED) repeat
     BOOT_-LINE_-STACK := PREPARSE IN_-STREAM
     LINE := CDAR BOOT_-LINE_-STACK
     PARSE_-NewExpr()
     pt := POP_-STACK_-1()                     -- get the parse tree
     pf := postTransform pt                    -- turn it into a parse form
     ast := parseTransform pf                  -- finally into an AST
     asts := cons([pf, ast], asts)
  IOCLEAR(IN_-STREAM, OUT_-STREAM)
  SHUT IN_-STREAM
  IN_-STREAM := savedInStream
  $InteractiveMode := savedInteractiveMode
  -- we accumulated the parse trees in reverse order
  -- of declarations.
  reverse asts