sh: Import arithmetic expression code from dash.

New features:
* proper lazy evaluation of || and &&
* ?: ternary operator
* executable is considerably smaller (8K on i386) because lex and yacc are
  no longer used

Differences from dash:
* arith_t instead of intmax_t
* imaxdiv() not used
* unset or null variables default to 0
* let/exp builtin (undocumented, will probably be removed later)

Obtained from:	dash

1 files changed, 91 insertions, 0 deletions

diff --git a/bin/sh/arith_yacc.h b/bin/sh/arith_yacc.h
new file mode 100644
index 0000000..5d8354f
--- /dev/null
+++ b/bin/sh/arith_yacc.h
@@ -0,0 +1,91 @@
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2007
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#define ARITH_ASS 1
+
+#define ARITH_OR 2
+#define ARITH_AND 3
+#define ARITH_BAD 4
+#define ARITH_NUM 5
+#define ARITH_VAR 6
+#define ARITH_NOT 7
+
+#define ARITH_BINOP_MIN 8
+#define ARITH_LE 8
+#define ARITH_GE 9
+#define ARITH_LT 10
+#define ARITH_GT 11
+#define ARITH_EQ 12
+#define ARITH_REM 13
+#define ARITH_BAND 14
+#define ARITH_LSHIFT 15
+#define ARITH_RSHIFT 16
+#define ARITH_MUL 17
+#define ARITH_ADD 18
+#define ARITH_BOR 19
+#define ARITH_SUB 20
+#define ARITH_BXOR 21
+#define ARITH_DIV 22
+#define ARITH_NE 23
+#define ARITH_BINOP_MAX 24
+
+#define ARITH_ASS_MIN 24
+#define ARITH_REMASS 24
+#define ARITH_BANDASS 25
+#define ARITH_LSHIFTASS 26
+#define ARITH_RSHIFTASS 27
+#define ARITH_MULASS 28
+#define ARITH_ADDASS 29
+#define ARITH_BORASS 30
+#define ARITH_SUBASS 31
+#define ARITH_BXORASS 32
+#define ARITH_DIVASS 33
+#define ARITH_ASS_MAX 34
+
+#define ARITH_LPAREN 34
+#define ARITH_RPAREN 35
+#define ARITH_BNOT 36
+#define ARITH_QMARK 37
+#define ARITH_COLON 38
+
+union yystype {
+	arith_t val;
+	char *name;
+};
+
+extern union yystype yylval;
+
+int yylex(void);