initial import of yapps from debian sources

git-svn-id: http://svn.stsci.edu/svn/ssb/etal/exyapps/trunk@356 d34015c8-bcbb-4646-8ac8-8ba5febf221d

1 files changed, 13 insertions, 0 deletions

diff --git a/examples/lisp.g b/examples/lisp.g
new file mode 100644
index 0000000..551e6f9
--- /dev/null
+++ b/examples/lisp.g
@@ -0,0 +1,13 @@
+parser Lisp:
+    ignore:      r'\s+'
+    token NUM:   r'[0-9]+'
+    token ID:    r'[-+*/!@$%^&=.a-zA-Z0-9_]+'
+    token STR:   r'"([^\\"]+|\\.)*"'
+
+    rule expr:   ID              {{ return ('id',ID) }}
+               | STR             {{ return ('str',eval(STR)) }}
+               | NUM             {{ return ('num',int(NUM)) }}
+               | r"\("           
+                        {{ e = [] }}             # initialize the list
+                 ( expr {{ e.append(expr) }} ) * # put each expr into the list
+                 r"\)"  {{ return e }}           # return the list