===================================
Auto-generated Code for Token Kinds					[TOC]
===================================

The source code for _strTokenKind()_ and the enum constants for _enum TokenKind_ 
can be generated from a text file that contains in each line the identifier for
a token kind. In __Quiz 22__ you wrote a program for that. This now can be
integrated into the project. By modifying the makefile we can make sure that
these source files always will be up to date.

:links: Quiz 22 -> doc:session20/page02

Solution for Quiz 22 (With Some Improvement)
============================================

On Unix system newline are encode with single character '\n' (ASCII 10). In the
Windows world two characters are used '\r' (ASCII 13) and '\n'. In the material
provided for Quiz 22 only the Unix case was handled correctly. Line are read
with _getline()_ and then the last character (the character before the null
byte) overwritten with a null byte. So for a Unix or Windows text files this
overwrites the \n'. For a Windows text file we actually have to overwrite the
second last character (the '\r') character.

---- CODE (file=session21/make_tokenkind.c, fold) ------------------------------
#include <stdio.h>
#include <stdlib.h>

void
printEnumHeader(FILE *out)
{
    fprintf(out, "enum TokenKind\n");
    fprintf(out, "{\n");
}

void
printEnumFooter(FILE *out)
{
    fprintf(out, "};\n");
}

void
printStrHeader(FILE *out)
{
    fprintf(out, "const char *\n");
    fprintf(out, "strTokenKind(enum TokenKind tokenKind)\n");
    fprintf(out, "{\n");
    fprintf(out, "%*sswitch (tokenKind) {\n", 4, "");
}

void
printStrFooter(FILE *out)
{
    fprintf(out, "%*sdefault:\n", 4, "");
    fprintf(out,
	    "%*sfprintf(stderr, \"internal error in strTokenKind: "
	    "tokenKind = %%d\",",
	    8, "");
    fprintf(out, "%*stokenKind);\n", 4, "");
    fprintf(out, "%*sfinalizeExit(1);\n", 4, "");
    fprintf(out, "%*sreturn \"\";\n", 4, "");
    fprintf(out, "%*s}\n", 4, "");
    fprintf(out, "}\n");
}

void
usage(const char *prg)
{
    fprintf(stderr, "usage: %s input output1 outpu2\n", prg);
    exit(1);
}

int
main(int argc, char *argv[])
{
    if (argc != 4) {
	usage(argv[0]);
    }

    FILE *in = fopen(argv[1], "r");
    FILE *outEnum = fopen(argv[2], "w");
    FILE *outStr = fopen(argv[3], "w");

    if (!in) {
	fprintf(stderr, "can not open input file '%s'\n", argv[1]);
    }
    if (!outEnum) {
	fprintf(stderr, "can not open output file '%s'\n", argv[2]);
    }
    if (!outStr) {
	fprintf(stderr, "can not open output file '%s'\n", argv[3]);
    }

    printEnumHeader(outEnum);
    printStrHeader(outStr);

    char *line = 0;
    size_t capacity = 0;
    ssize_t len;
    while ((len = getline(&line, &capacity, in)) > 0) {
	line[len - 2] == '\r' ?  (line[len - 2] = 0) : (line[len - 1] = 0);
	fprintf(outEnum, "%*s%s,\n", 4, "", line);

	fprintf(outStr, "%*scase %s:\n", 4, "", line);
	fprintf(outStr, "%*sreturn \"%s\";\n", 8, "", line);
    }
    free(line);

    printEnumFooter(outEnum);
    printStrFooter(outStr);

    fclose(in);
    fclose(outEnum);
    fclose(outStr);
}
--------------------------------------------------------------------------------


My Status of the ABC Project
============================

---- SHELL (path=session21/git, hide) ------------------------------------------
rm -rf abc
git clone git@gitlab.com:uni-ulmulm-university-department-of-numerical-analysis/abc.git
git config --global advice.detachedHead false
--------------------------------------------------------------------------------

---- SHELL (path=session21/git/abc, hide) --------------------------------------
git checkout auto-gen6
--------------------------------------------------------------------------------

In my project the makefile was modified so that program with the prefix _xgen_
are considered to generate source files that are required. Hence, the program
~make_tokenkind.c~ was renamed into ~xgen_tokenkind.c~.

The source files that need to be generated can be specified in a variable. Here
you can see that first the executable ~xgen_tokenkind~ get created and then
form _tokenkind.txt_ the source files ~gen_tokenkind.h~ and
~gen_strtokenkind.c~ are generated. If ~xgen_tokenkind.c~ or ~tokenkind.txt~
will be changed then the generated source files will be updated and all object
files and targets that depend on the generated source files.

---- SHELL (path=session21/git/abc) --------------------------------------------
make
--------------------------------------------------------------------------------

Here all files from my project at the current status:

:import: session21/git/abc/expr.c [fold]
:import: session21/git/abc/expr.h [fold]
:import: session21/git/abc/finalize.c [fold]
:import: session21/git/abc/finalize.h [fold]
:import: session21/git/abc/lexer.c [fold]
:import: session21/git/abc/lexer.h [fold]
:import: session21/git/abc/Makefile [fold]
:import: session21/git/abc/parser.c [fold]
:import: session21/git/abc/parser.h [fold]
:import: session21/git/abc/README.md [fold]
:import: session21/git/abc/str.c [fold]
:import: session21/git/abc/str.h [fold]
:import: session21/git/abc/sym.c [fold]
:import: session21/git/abc/sym.h [fold]
:import: session21/git/abc/test_calc.in [fold]
:import: session21/git/abc/test_lexer.in [fold]
:import: session21/git/abc/tokenkind.c [fold]
:import: session21/git/abc/tokenkind.h [fold]
:import: session21/git/abc/tokenkind.txt [fold]
:import: session21/git/abc/ustr.c [fold]
:import: session21/git/abc/ustr.h [fold]
:import: session21/git/abc/xgen_tokenkind.c [fold]
:import: session21/git/abc/xtest_calc.c [fold]
:import: session21/git/abc/xtest_expr.c [fold]
:import: session21/git/abc/xtest_finalize.c [fold]
:import: session21/git/abc/xtest_lexer.c [fold]
:import: session21/git/abc/xtest_lexer_sanity.c [fold]
:import: session21/git/abc/xtest_sym.c [fold]
:import: session21/git/abc/xtest_ustr.c [fold]