5 files changed, 213 insertions, 0 deletions
diff --git a/works/life/compile-principle-experiment/3/lex.l b/works/life/compile-principle-experiment/3/lex.l
new file mode 100644
index 0000000..ddea92d
--- /dev/null
+++ b/works/life/compile-principle-experiment/3/lex.l
@@ -0,0 +1,17 @@
+%{
+#include "main.h"
+#include "syn.h"
+%}
+%option noyywrap
+%%
+[ \t]	{ ; }	/* skip blanks and tabs */
+[0-9]+\.?|[0-9]*\.[0-9]+ {
+	sscanf(yytext, "%lf", &yylval.val); return NUMBER; }
+[a-zA-Z][a-zA-Z0-9]* {
+	Symbol *s;
+	if ((s=cru_symbol_lookup(yytext)) == 0)
+		s = cru_symbol_install(yytext, UNDEF, (SymbolValue)0.0);
+	yylval.sym = s;
+	return s->type == UNDEF ? VAR : s->type; }
+\n	{ lineno++; return '\n'; }   /* everything else */
+.	{ return yytext[0]; }
diff --git a/works/life/compile-principle-experiment/3/main.c b/works/life/compile-principle-experiment/3/main.c
new file mode 100644
index 0000000..7cd8c28
--- /dev/null
+++ b/works/life/compile-principle-experiment/3/main.c
@@ -0,0 +1,107 @@
+#include "main.h"
+
+#include "syn.h"
+
+#include <errno.h>
+#include <math.h>
+#include <setjmp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static Symbol *symlist = 0; /* symbol table: linked list */
+
+void *emalloc(size_t n) /* check return from malloc */
+{
+  void *p = malloc(n);
+  if (p == 0)
+    execerror("out of memory", (char *)0);
+  return p;
+}
+
+Symbol *cru_symbol_lookup(const char *name) {
+  for (Symbol *sp = symlist; sp != NULL; sp = sp->next)
+    if (strcmp(sp->name, name) == 0)
+      return sp;
+  return NULL;
+}
+
+Symbol *cru_symbol_install(const char *name, int type, SymbolValue value) {
+  Symbol *sp = (Symbol *)emalloc(sizeof(Symbol));
+  sp->name = emalloc(strlen(name) + 1);
+  strcpy(sp->name, name);
+  sp->type = type;
+  sp->value = value;
+  sp->next = symlist;
+  symlist = sp;
+  return sp;
+}
+
+jmp_buf begin;
+int lineno;
+
+void warning(const char *s, const char *t) {
+  fprintf(stderr, "%s", s);
+  if (t)
+    fprintf(stderr, " %s", t);
+  fprintf(stderr, " near line %d\n", lineno);
+}
+
+void yyerror(const char *s) { warning(s, NULL); }
+
+void execerror(const char *s, const char *t) {
+  warning(s, t);
+  longjmp(begin, 0);
+}
+
+double errcheck(double result, const char *name) {
+  if (errno == EDOM) {
+    errno = 0;
+    execerror(name, "argument out of domain");
+  } else if (errno == ERANGE) {
+    errno = 0;
+    execerror(name, "result out of range");
+  }
+  return result;
+}
+
+double Log(double x) { return errcheck(log(x), "log"); }
+double Log10(double x) { return errcheck(log10(x), "log10"); }
+double Sqrt(double x) { return errcheck(sqrt(x), "sqrt"); }
+double Exp(double x) { return errcheck(exp(x), "exp"); }
+double Pow(double x, double y) { return errcheck(pow(x, y), "exponentiation"); }
+double integer(double x) { return (double)(long)x; }
+
+static struct { /* Constants */
+  char *name;
+  double cval;
+} consts[] = {
+    {"PI", 3.14159265358979323846},    {"E", 2.71828182845904523536},
+    {"GAMMA", 0.57721566490153286060}, {"DEG", 57.29577951308232087680},
+    {"PHI", 1.61803398874989484820},
+};
+
+static struct { /* Built-ins */
+  char *name;
+  double (*func)();
+} builtins[] = {
+    {"sin", sin},   {"cos", cos},     {"atan", atan},
+    {"log", Log},   {"log10", Log10}, {"exp", Exp},
+    {"sqrt", Sqrt}, {"int", integer}, {"abs", fabs},
+};
+
+void init() {
+  for (int i = 0; i < sizeof(consts) / sizeof(*consts); i++)
+    cru_symbol_install(consts[i].name, VAR, (SymbolValue)consts[i].cval);
+  for (int i = 0; i < sizeof(builtins) / sizeof(*builtins); i++) {
+    cru_symbol_install(builtins[i].name, BLTIN, (SymbolValue)builtins->func);
+  }
+}
+
+int main(int argc, char **argv) {
+  init();
+  (void)setjmp(begin);
+  yyparse();
+
+  return 0;
+}
diff --git a/works/life/compile-principle-experiment/3/main.h b/works/life/compile-principle-experiment/3/main.h
new file mode 100644
index 0000000..9bd6e56
--- /dev/null
+++ b/works/life/compile-principle-experiment/3/main.h
@@ -0,0 +1,25 @@
+#pragma once
+
+typedef union SymbolValue {
+  double val;
+  double (*ptr)();
+} SymbolValue;
+
+typedef struct Symbol {
+  char *name;
+  int type;
+  SymbolValue value;
+  struct Symbol *next;
+} Symbol;
+
+Symbol *cru_symbol_lookup(const char *name);
+Symbol *cru_symbol_install(const char *name, int type, SymbolValue value);
+
+double Pow(double x, double y);
+
+int yylex();
+int yyparse();
+void yyerror(const char *s);
+
+extern int lineno;
+void execerror(const char *s, const char *t);
diff --git a/works/life/compile-principle-experiment/3/makefile b/works/life/compile-principle-experiment/3/makefile
new file mode 100644
index 0000000..cf6333c
--- /dev/null
+++ b/works/life/compile-principle-experiment/3/makefile
@@ -0,0 +1,22 @@
+main: main.o lex.o syn.o
+	cc lex.o syn.o main.o -o main
+
+main.o: main.c main.h syn.h
+	cc -c -o main.o main.c
+
+lex.c: lex.l
+	flex  -o lex.c lex.l
+
+lex.o: lex.c syn.h main.h
+	cc -c -o lex.o lex.c
+
+syn.c syn.h: syn.y
+	bison syn.y -d -o syn.c
+
+syn.o: syn.c syn.h main.h
+	cc -c -o syn.o syn.c
+
+PHONY: clean
+
+clean:
+	rm -f *.o lex.c syn.c syn.h main
diff --git a/works/life/compile-principle-experiment/3/syn.y b/works/life/compile-principle-experiment/3/syn.y
new file mode 100644
index 0000000..80abb17
--- /dev/null
+++ b/works/life/compile-principle-experiment/3/syn.y
@@ -0,0 +1,42 @@
+%{
+#include "main.h"
+#include <stdio.h>
+%}
+%union {
+	double	val;	/* actual value */
+	Symbol	*sym;	/* symbol table pointer */
+}
+%token	<val>	NUMBER
+%token	<sym>	VAR BLTIN UNDEF
+%type	<val>	expr asgn
+%right	'='
+%left	'+' '-'
+%left	'*' '/'
+%left	UNARYMINUS
+%right	'^'	/* exponentiation */
+%%
+list:	  /* nothing */
+	| list '\n'
+	| list asgn '\n'
+	| list expr '\n'	{ printf("\t%.8g\n", $2); }
+	| list error '\n'	{ yyerrok; }
+	;
+asgn:	  VAR '=' expr { $$=$1->value.val=$3; $1->type = VAR; }
+	;
+expr:	  NUMBER
+	| VAR {	if ($1->type == UNDEF)
+		    execerror("undefined variable", $1->name);
+		$$ = $1->value.val; }
+	| BLTIN '(' expr ')'	{ $$ = (*($1->value.ptr))($3); }
+	| expr '+' expr	{ $$ = $1 + $3; }
+	| expr '-' expr	{ $$ = $1 - $3; }
+	| expr '*' expr	{ $$ = $1 * $3; }
+	| expr '/' expr	{
+		if ($3 == 0.0)
+			execerror("division by zero", "");
+		$$ = $1 / $3; }
+	| expr '^' expr	{ $$ = Pow($1, $3); }
+	| '(' expr ')'	{ $$ = $2; }
+	| '-' expr  %prec UNARYMINUS  { $$ = -$2; }
+	;
+%%