X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/e82f7154f65062d9ac8b9677862774498b331058..17be1d6b52cc22403bcfec5e8547bf612d214690:/scan.h

diff --git a/scan.h b/scan.h
index f08fe01..eee6f61 100644
--- a/scan.h
+++ b/scan.h
@@ -1,10 +1,10 @@
 /* -*-c-*-
  *
- * $Id: scan.h,v 1.1 1999/07/01 08:56:23 mdw Exp $
+ * $Id: scan.h,v 1.2 1999/07/26 23:24:33 mdw Exp $
  *
  * Character scanners
  *
- * (c) 1999 Mark Wooding
+ * (c) 1999 Straylight/Edgeware
  */
 
 /*----- Licensing notice --------------------------------------------------* 
@@ -29,8 +29,12 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: scan.h,v $
- * Revision 1.1  1999/07/01 08:56:23  mdw
- * Initial revision
+ * Revision 1.2  1999/07/26 23:24:33  mdw
+ * Complete rewrite.  Allow a list of character sources to enable changes
+ * during parsing of syntactic constructs.
+ *
+ * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
+ * Initial revision.
  *
  */
 
@@ -49,43 +53,133 @@
 
 /*----- Data structures ---------------------------------------------------*/
 
-/* --- A configuration scanner --- */
+/* --- A low-level scanner source --- */
+
+typedef struct scansrc {
+  struct scansrc *next;			/* Next one in the list */
+  struct scansrc_ops *ops;		/* Pointer to operations table */
+  char *src;				/* Name of this source */
+  int line;				/* Current line number */
+  int pushback;				/* Pushback character */
+  char *tok;				/* Token pushback */
+  unsigned t;				/* Token type pushback */
+} scansrc;
+
+/* --- Scanner source operations --- */
 
-typedef struct scan_ops {
-  int (*scan)(void */*p*/);		/* Character scan function */
-  void (*unscan)(int /*ch*/, void */*p*/); /* Character pushback function */
-} scan_ops;
+typedef struct scansrc_ops {
+  int (*scan)(scansrc */*ss*/);		/* Read another character */
+  void (*destroy)(scansrc */*ss*/);	/* Destroy an unwanted source */
+} scansrc_ops;
+
+/* --- A character scanner --- */
 
 typedef struct scanner {
-  scan_ops *ops;			/* Pointer to scanner operations */
-  const char *src;			/* Name of this source */
-  int line;				/* Current line number */
+  scansrc *head, **tail;		/* Scanner list head and tail */
   int t;				/* Token type */
   dstr d;				/* Current token value */
 } scanner;
 
-/*----- Scanners provided -------------------------------------------------*/
+/*----- Particular scanner types ------------------------------------------*/
+
+/* --- @scan_file@ --- *
+ *
+ * Arguments:	@FILE *fp@ = pointer to file descriptor
+ *		@char *name@ = pointer to source file name
+ *		@unsigned f@ = flags
+ *
+ * Returns:	A scanner source.
+ *
+ * Use:		Creates a new scanner source for reading from a file.
+ */
+
+extern scansrc *scan_file(FILE */*fp*/, char */*name*/, unsigned /*f*/);
+
+#define SCF_NOCLOSE 1u
+#define SCF_FREENAME 2u
+
+/* --- @scan_argv@ --- *
+ *
+ * Arguments:	@char **av@ = pointer to argument array (null terminated)
+ *
+ * Returns:	A scanner source.
+ *
+ * Use:		Creates a new scanner source for reading from an @argv@
+ *		array.
+ */
+
+extern scansrc *scan_argv(char **/*av*/);
+
+/*----- General scanner handling ------------------------------------------*/
+
+/* --- @scan@ --- *
+ *
+ * Arguments:	@scanner *sc@ = pointer to main scanner context
+ *
+ * Returns:	Character read, or end-of-file.
+ *
+ * Use:		Scans a character from a source of characters.
+ */
+
+extern int scan(scanner */*sc*/);    
 
-/* --- The @argv@ scanner --- */
+/* --- @unscan@ --- *
+ *
+ * Arguments:	@scanner *sc@ = pointer to main scanner context
+ *		@int ch@ = character to unscan
+ *
+ * Returns:	---
+ *
+ * Use:		Scans a character from a source of characters.
+ */
 
-typedef struct scan_argvctx {
-  scanner sc;				/* Scanner base structure */
-  char *p;				/* Pointer to next character */
-  char **pp;				/* Pointer to next string */
-  int ch;				/* Pushback character */
-} scan_argvctx;
+extern void unscan(scanner */*sc*/, int /*ch*/);
 
-extern void scan_argvinit(scan_argvctx */*c*/, char **/*pp*/);
+/* --- @scan_push@ --- *
+ *
+ * Arguments:	@scanner *sc@ = pointer to main scanner context
+ *		@scansrc *ss@ = souorce to push
+ *
+ * Returns:	---
+ *
+ * Use:		Pushes a scanner source onto the front of the queue.
+ */
 
-/* --- The file scanner --- */
+extern void scan_push(scanner */*sc*/, scansrc */*ss*/);
 
-typedef struct scan_filectx {
-  scanner sc;				/* Scanner base structure */
-  FILE *fp;				/* Stream pointer */
-} scan_filectx;
+/* --- @scan_add@ --- *
+ *
+ * Arguments:	@scanner *sc@ = pointer to main scanner context
+ *		@scansrc *ss@ = souorce to push
+ *
+ * Returns:	---
+ *
+ * Use:		Adds a scanner source onto the end of the queue.
+ */
+
+extern void scan_add(scanner */*sc*/, scansrc */*ss*/);
+
+/* --- @scan_create@ --- *
+ *
+ * Arguments:	@scanner *sc@ = scanner context to initialize
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes a scanner block ready for use.
+ */
+
+extern void scan_create(scanner */*sc*/);
+
+/* --- @scan_destroy@ --- *
+ *
+ * Arguments:	@scanner *sc@ = pointer to scanner context
+ *
+ * Returns:	---
+ *
+ * Use:		Destroys a scanner and all the sources attached to it.
+ */
 
-extern void scan_fileinit(scan_filectx */*c*/,
-			  FILE */*fp*/, const char */*file*/);
+extern void scan_destroy(scanner */*sc*/);
 
 /*----- That's all, folks -------------------------------------------------*/