+/* unlit.c Wed Dec 5 17:16:24 GMT 1990
+ *
+ * Literate script filter. In contrast with the format used by most
+ * programming languages, a literate script is a program in which
+ * comments are given the leading role, whilst program text must be
+ * explicitly flagged as such by placing a `>' character in the first
+ * column on each line. It is hoped that this style of programming will
+ * encourage the writing of accurate and clearly documented programs
+ * in which the writer may include motivating arguments, examples
+ * and explanations.
+ *
+ * Unlit is a filter that can be used to strip all of the comment lines
+ * out of a literate script file. The command format for unlit is:
+ * unlit [-n] [-q] ifile ofile
+ * where ifile and ofile are the names of the input (literate script) and
+ * output (raw program) files respectively. Either of these names may
+ * be `-' representing the standard input or the standard output resp.
+ * A number of rules are used in an attempt to guard against the most
+ * common errors that are made when writing literate scripts:
+ * 1) Empty script files are not permitted. A file in which no lines
+ * begin with `>' usually indicates a file in which the programmer
+ * has forgotten about the literate script convention.
+ * 2) A line containing part of program definition (i.e. preceeded by `>')
+ * cannot be used immediately before or after a comment line unless
+ * the comment line is blank. This error usually indicates that
+ * the `>' character has been omitted from a line in a section of
+ * program spread over a number of lines.
+ * Using the -q (quiet) flag suppresses the signalling of these error
+ * conditions. The default behaviour can be selected explicitly using
+ * the -n (noisy) option so that any potential errors in the script file
+ * are reported.
+ *
+ * The original idea for the use of literate scripts is due to Richard
+ * Bird of the programming Research Group, Oxford and was initially
+ * adopted for use in the implementation of the functional programming
+ * language Orwell used for teaching in Oxford. This idea has subsequently
+ * been borrowed in a number of other language implementations.
+ *
+ * Modified to understand \begin{code} ... \end{code} used in Glasgow. -- LA
+ * And \begin{pseudocode} ... \end{pseudocode}. -- LA
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+#define NULLSTR ((char *)0)
+#define DEFNCHAR '>'
+#define MISSINGBLANK "unlit: Program line next to comment"
+#define EMPTYSCRIPT "unlit: No definitions in file (perhaps you forgot the '>'s?)"
+#define USAGE "usage: unlit [-q] [-n] [-c] [-#] [-P] [-h label] file1 file2\n"
+#define CANNOTOPEN "unlit: cannot open \"%s\"\n"
+#define CANNOTWRITE "unlit: error writing \"%s\"\n"
+#define CANNOTWRITESTDOUT "unlit: error writing standard output\n"
+#define DISTINCTNAMES "unlit: input and output filenames must differ\n"
+#define MISSINGENDCODE "unlit: missing \\end{code}\n"
+
+#define BEGINCODE "\\begin{code}"
+#define LENBEGINCODE 12
+#define ENDCODE "\\end{code}"
+#define LENENDCODE 10
+#ifdef PSEUDOCODE
+/* According to Will Partain, the inventor of pseudocode, this gone now. */
+#define MISSINGENDPSEUDOCODE "unlit: missing \\end{pseudocode}\n"
+#define BEGINPSEUDOCODE "\\begin{pseudocode}"
+#define LENBEGINPSEUDOCODE 18
+#define ENDPSEUDOCODE "\\end{pseudocode}"
+#define LENENDPSEUDOCODE 16
+#endif
+
+typedef enum { START, BLANK, TEXT, DEFN, BEGIN, /*PSEUDO,*/ END, HASH, SHEBANG } line;
+#define isWhitespace(c) (c==' ' || c=='\t' || c=='\r')
+#define isLineTerm(c) (c=='\n' || c==EOF)
+
+static int noisy = 1; /* 0 => keep quiet about errors, 1 => report errors */
+static int errors = 0; /* count the number of errors reported */
+static int crunchnl = 0; /* don't print \n for removed lines */
+static int leavecpp = 1; /* leave preprocessor lines */
+static int ignore_shebang = 1; /* Leave out shebang (#!) lines */
+static int no_line_pragma = 0; /* Leave out initial line pragma */
+
+static char* prefix_str = NULL; /* Prefix output with a string */
+
+static char *ofilename = NULL;
+
+/* complain(file,line,what)
+ *
+ * print error message `what' for `file' at `line'. The error is suppressed
+ * if noisy is not set.
+ */
+
+complain(file, lin, what)
+char *file;
+char *what;
+int lin; {
+ if (noisy) {
+ if (file)
+ fprintf(stderr, "%s ", file);
+ fprintf(stderr,"line %d: %s\n",lin,what);
+ errors++;
+ }
+}
+
+writeerror()
+{
+ if (!strcmp(ofilename,"-")) {
+ fprintf(stderr, CANNOTWRITESTDOUT);
+ } else {
+ fprintf(stderr, CANNOTWRITE, ofilename);
+ }
+ exit(1);
+}
+
+myputc(c, ostream)
+char c;
+FILE *ostream; {
+ if (putc(c,ostream) == EOF) {
+ writeerror();
+ }
+}
+
+#define TABPOS 8
+
+/* As getc, but does TAB expansion */
+int
+egetc(istream)
+FILE *istream;
+{
+ static int spleft = 0;
+ static int linepos = 0;
+ int c;
+
+ if (spleft > 0) {
+ spleft--;
+ linepos++;
+ return ' ';
+ }
+ c = getc(istream);
+ if (c == EOF)
+ return c;
+ else if (c == '\n' || c == '\f') {
+ linepos = 0;
+ return c;
+ } else if (c == '\t') {
+ spleft = TABPOS - linepos % TABPOS;
+ spleft--;
+ linepos++;
+ return ' ';
+ } else {
+ linepos++;
+ return c;
+ }
+
+}
+
+/* readline(istream, ostream)
+ *
+ * Read a line from the input stream `istream', and return a value
+ * indicating whether that line was:
+ * BLANK (whitespace only),
+ * DEFN (first character is DEFNCHAR),
+ * TEXT (a line of text)
+ * BEGIN (a \begin{code} line)
+ * PSEUDO (a \begin{pseodocode} line)
+ * HASH (a preprocessor line)
+ * or END (indicating an EOF).
+ * Lines of type DEFN are copied to the output stream `ostream'
+ * (without the leading DEFNCHAR). BLANK and TEXT lines are
+ * replaced by empty (i.e. blank lines) in the output stream, so
+ * that error messages refering to line numbers in the output file
+ * can also be used to locate the corresponding line in the input
+ * stream.
+ */
+
+line readline(istream,ostream)
+FILE *istream, *ostream; {
+ int c, c1;
+ char buf[100];
+ int i;
+
+ c = egetc(istream);
+
+ if (c==EOF)
+ return END;
+
+ if ( c == '#' ) {
+ if ( ignore_shebang ) {
+ c1 = egetc(istream);
+ if ( c1 == '!' ) {
+ while (c=egetc(istream), !isLineTerm(c)) ;
+ return SHEBANG;
+ }
+ myputc(c, ostream);
+ c=c1;
+ }
+ if ( leavecpp ) {
+ myputc(c, ostream);
+ while (c=egetc(istream), !isLineTerm(c))
+ myputc(c,ostream);
+ myputc('\n',ostream);
+ return HASH;
+ }
+ }
+
+ if (c==DEFNCHAR) {
+/* myputc(' ',ostream);*/
+ while (c=egetc(istream), !isLineTerm(c))
+ myputc(c,ostream);
+ myputc('\n',ostream);
+ return DEFN;
+ }
+
+ if (!crunchnl)
+ myputc('\n',ostream);
+
+ while (isWhitespace(c))
+ c=egetc(istream);
+ if (isLineTerm(c))
+ return BLANK;
+
+ i = 0;
+ buf[i++] = c;
+ while (c=egetc(istream), !isLineTerm(c))
+ if (i < sizeof buf - 1)
+ buf[i++] = c;
+ while(i > 0 && isspace(buf[i-1]))
+ i--;
+ buf[i] = 0;
+ if (strcmp(buf, BEGINCODE) == 0)
+ return BEGIN;
+#ifdef PSEUDOCODE
+ else if (strcmp(buf, BEGINPSEUDOCODE) == 0)
+ return PSEUDO;
+#endif
+ else
+ return TEXT;
+}
+
+
+/* unlit(file,istream,ostream)
+ *
+ * Copy the file named `file', accessed using the input stream `istream'
+ * to the output stream `ostream', removing any comments and checking
+ * for bad use of literate script features:
+ * - there should be at least one BLANK line between a DEFN and TEXT
+ * - there should be at least one DEFN line in a script.
+ */
+
+unlit(file, istream, ostream)
+char *file;
+FILE *istream;
+FILE *ostream; {
+ line last, this=START;
+ int linesread=0;
+ int defnsread=0;
+
+ do {
+ last = this;
+ this = readline(istream, ostream);
+ linesread++;
+ if (this==DEFN)
+ defnsread++;
+ if (last==DEFN && this==TEXT)
+ complain(file, linesread-1, MISSINGBLANK);
+ if (last==TEXT && this==DEFN)
+ complain(file, linesread, MISSINGBLANK);
+ if (this == BEGIN) {
+ /* start of code, copy to end */
+ char lineb[1000];
+ for(;;) {
+ if (fgets(lineb, sizeof lineb, istream) == NULL) {
+ complain(file, linesread, MISSINGENDCODE);
+ exit(1);
+ }
+ linesread++;
+ if (strncmp(lineb,ENDCODE,LENENDCODE) == 0) {
+ myputc('\n', ostream);
+ break;
+ }
+ fputs(lineb, ostream);
+ }
+ defnsread++;
+ }
+#ifdef PSEUDOCODE
+ if (this == PSEUDO) {
+ char lineb[1000];
+ for(;;) {
+ if (fgets(lineb, sizeof lineb, istream) == NULL) {
+ complain(file, linesread, MISSINGENDPSEUDOCODE);
+ exit(1);
+ }
+ linesread++;
+ myputc('\n', ostream);
+ if (strncmp(lineb,ENDPSEUDOCODE,LENENDPSEUDOCODE) == 0) {
+ break;
+ }
+ }
+ }
+#endif
+ } while(this!=END);
+
+ if (defnsread==0)
+ complain(file,linesread,EMPTYSCRIPT);
+}
+
+/* main(argc, argv)
+ *
+ * Main program. Processes command line arguments, looking for leading:
+ * -q quiet mode - do not complain about bad literate script files
+ * -n noisy mode - complain about bad literate script files.
+ * -r remove cpp droppings in output.
+ * -P don't output any CPP line pragmas.
+ * Expects two additional arguments, a file name for the input and a file
+ * name for the output file. These two names must normally be distinct.
+ * An exception is made for the special name "-" which can be used in either
+ * position to specify the standard input or the standard output respectively.
+ */
+
+main(argc,argv)
+int argc;
+char **argv; {
+ FILE *istream, *ostream;
+ char *file;
+
+ for (argc--, argv++; argc > 0; argc--, argv++)
+ if (strcmp(*argv,"-n")==0)
+ noisy = 1;
+ else if (strcmp(*argv,"-q")==0)
+ noisy = 0;
+ else if (strcmp(*argv,"-c")==0)
+ crunchnl = 1;
+ else if (strcmp(*argv,"-P")==0)
+ no_line_pragma = 1;
+ else if (strcmp(*argv,"-h")==0) {
+ if (argc > 1) {
+ argc--; argv++;
+ if (prefix_str)
+ free(prefix_str);
+ prefix_str = (char*)malloc(sizeof(char)*(1+strlen(*argv)));
+ if (prefix_str)
+ strcpy(prefix_str, *argv);
+ }
+ } else if (strcmp(*argv,"-#")==0)
+ ignore_shebang = 0;
+ else
+ break;
+
+ if (argc!=2) {
+ fprintf(stderr, USAGE);
+ exit(1);
+ }
+
+ if (strcmp(argv[0],argv[1])==0 && strcmp(argv[0],"-")!=0) {
+ fprintf(stderr, DISTINCTNAMES);
+ exit(1);
+ }
+
+ file = argv[0];
+ if (strcmp(argv[0], "-")==0) {
+ istream = stdin;
+ file = "stdin";
+ }
+ else
+ if ((istream=fopen(argv[0], "r")) == NULL) {
+ fprintf(stderr, CANNOTOPEN, argv[0]);
+ exit(1);
+ }
+
+ ofilename=argv[1];
+ if (strcmp(argv[1], "-")==0)
+ ostream = stdout;
+ else
+ if ((ostream=fopen(argv[1], "w")) == NULL) {
+ fprintf(stderr, CANNOTOPEN, argv[1]);
+ exit(1);
+ }
+
+ /* Prefix the output with line pragmas */
+ if (!no_line_pragma && prefix_str) {
+ /* Both GHC and CPP understand the #line pragma.
+ * We used to throw in both a #line and a {-# LINE #-} pragma
+ * here, but CPP doesn't understand {-# LINE #-} so it thought
+ * the line numbers were off by one. We could put the {-# LINE
+ * #-} before the #line, but there's no point since GHC
+ * understands #line anyhow. --SDM 8/2003
+ */
+ fprintf(ostream, "#line 1 \"%s\"\n", prefix_str);
+ }
+
+ unlit(file, istream, ostream);
+
+ if (istream != stdin) fclose(istream);
+ if (ostream != stdout) {
+ if (fclose(ostream) == EOF) {
+ writeerror();
+ }
+ }
+
+ exit(errors==0 ? 0 : 1);
+}