1 files changed, 35 insertions, 0 deletions
diff --git a/taccle/examples/infix_calc.tac b/taccle/examples/infix_calc.tac
new file mode 100644
index 0000000..95ef2ee
--- /dev/null
+++ b/taccle/examples/infix_calc.tac
@@ -0,0 +1,35 @@
+# $Id: infix_calc.tac,v 1.1 2004/09/29 16:23:28 tang Exp $
+
+# This example demonstrates how taccle handles operator precedence.
+# The code is shamelessly borrowed from the GNU Bison info manual.
+
+# taccle Declarations
+%token ID NEWLINE
+%left '-' '+'
+%left '*' '/'
+%left NEG       # negation--unary minus
+%right '^'      # exponentiation
+
+# Grammar follows
+%%
+input:    # empty string
+        | input line
+;
+
+line:     NEWLINE
+        | exp NEWLINE        { puts [format "\t%.10g" $1] }
+;
+
+exp:      ID                 { set _ $1                   }
+        | exp '+' exp        { set _ [expr {$1 + $3}]     }
+        | exp '-' exp        { set _ [expr {$1 - $3}]     }
+        | exp '*' exp        { set _ [expr {$1 * $3}]     }
+        | exp '/' exp        { set _ [expr {$1 / $3}]     }
+        | '-' exp  %prec NEG { set _ [expr {-1.0 * $2}]   }
+        | exp '^' exp        { set _ [expr {pow($1, $3)}] }
+        | '(' exp ')'        { set _ $2                   }
+;
+%%
+
+source simple_scanner.tcl
+yyparse