diff --git a/application.py b/application.py
index ceff134..f63357c 100755
--- a/application.py
+++ b/application.py
@@ -179,6 +179,7 @@ class Application(object):
             'awk', 'shell', 'shellmini', 'fstab', 'yacc', 'pipe', 'mbox',
             'error', 'lua', 'lily', 'forth', 'ebnf', 'colortest', 'go',
             'inform6', 'scala', 'markdown', 'roy', 'twine', 'idris', 'rust',
+            'bosatsu',
         )
         for name in names:
             exec("import mode.%s; mode.%s.install(self)" % (name, name))
diff --git a/mode/bosatsu.py b/mode/bosatsu.py
new file mode 100644
index 0000000..1cc3925
--- /dev/null
+++ b/mode/bosatsu.py
@@ -0,0 +1,120 @@
+import commands, os.path, re, string, sys, traceback
+import color, completer, context, default, mode, method, regex, tab
+from lex import Grammar, PatternRule, RegionRule, OverridePatternRule
+
+from mode.python import StringGrammar1, StringGrammar2
+
+class PackageGrammar(Grammar):
+    rules = [
+        PatternRule('whitespace', r'(?: |\t)+'),
+        PatternRule('name', r'[a-zA-Z_][a-zA-Z0-9]*'),
+        PatternRule('sep', r'/'),
+    ]
+
+class BosatsuGrammar(Grammar):
+    rules = [
+        # whitespace
+        PatternRule('whitespace', r'(?: |\t)+'),
+        PatternRule('eol', r'\n$'),
+
+        # basic 
+        PatternRule('bosatsu.comment', r'#.*$'),
+        #PatternRule('bosatsu.integer', r'(?<![\.0-9a-zA-Z_])(?:0|-?[1-9][0-9]*)(?![\.0-9a-zA-Z_])'),
+        PatternRule('bosatsu.integer', r'(?:0|-?[1-9][0-9]*)(?![\.0-9a-zA-Z_])'),
+
+        # match keywords early
+        PatternRule('bosatsu.keyword', '(?:struct|recur|package|operator|match|import|if|forall|for|external|export|enum|else|def|_)(?![a-zA-Z0-9_])'),
+
+        # use look-behind assertion to detect package/def/operator
+        RegionRule('bosatsu.package', '(?<=(?<![a-zA-Z0-9_])package )', PackageGrammar, '\n$'),
+        PatternRule('bosatsu.def', '(?<=(?<![a-zA-Z0-9_])operator )[^:( ]+'),
+        PatternRule('bosatsu.def', '(?<=(?<![a-zA-Z0-9_])def )[a-zA-Z_][a-zA-Z0-9_]*'),
+
+        # detect a bunch of different syntax-y stuff + predef methods
+        PatternRule('bosatsu.builtin', r'(?:->|:|=|\.)(?![/%\*\-+<>!$&^|?~=:])'),
+        PatternRule('bosatsu.predef', r'(?:uncurry3|uncurry2|trace|times|string_Order|string_Order_fn|sub|reverse_concat|reverse|remove_key|range_fold|range|mod_Int|map_List|items|int_loop|get_key|gcd_Int|foldLeft|flat_map_List|eq_Int|empty_Dict|clear_Dict|div|concat|cmp_Int|add_key|add)(?![a-zA-Z0-9_])'),
+        PatternRule('bosatsu.delimiter', r'\(|\)|\[|\]|,'),
+        PatternRule('bosatsu.operator', r'[/%\*\-+<>!$&^|?~]+|=[/%\*\-+<>!$&^|?~=]+'),
+
+        # user-defined types and names
+        PatternRule('bosatsu.type', r'[A-Z][a-zA-Z_]*'),
+        PatternRule('bosatsu.bareword', r'[a-z_][a-zA-Z_]*'),
+
+        # python style strings
+        RegionRule('bosatsu.string', r'"', StringGrammar2, r'"'),
+        RegionRule('bosatsu.string', r"'", StringGrammar1, r"'"),
+
+        # we want to highlight everything, so show any unmatched
+        # characters as a syntax error
+        PatternRule('bosatsu.unknown', r'.'),
+    ]
+
+# white is for delimiters, operators, numbers
+default = ('default', 'default')
+
+# magenta is for reserved words
+lo_magenta = ('magenta202', 'default')
+hi_magenta = ('magenta505', 'default')
+
+# red is for comments
+lo_red = ('red300', 'default')
+hi_red = ('red511', 'default')
+
+# orange is unused
+hi_orange = ('yellow531', 'default')
+lo_orange = ('yellow520', 'default')
+
+# yellow is for class names
+hi_yellow = ('yellow551', 'default')
+lo_yellow = ('yellow330', 'default')
+
+# green is for strings
+lo_green = ('green030', 'default')
+hi_green = ('green050', 'default')
+
+# cyan is for keywords and some operators
+lo_cyan = ('cyan033', 'default')
+hi_cyan = ('cyan155', 'default')
+
+# blue is for functions and methods
+lo_blue = ('blue113', 'default')
+hi_blue = ('blue225', 'default')
+
+class Bosatsu(mode.Fundamental):
+    description = '''
+    Mode for Oscar Boykin's language Bosatsu.
+'''
+    name        = 'Bosatsu'
+    extensions  = ['.bosatsu']
+    grammar     = BosatsuGrammar
+    opentokens  = ('bosatsu.delimiter',)
+    opentags    = {'(': ')', '[': ']'}
+    closetokens = ('bosatsu.delimiter',)
+    closetags   = {')': '(', ']': '['}
+    commentc    = '#'
+    colors      = {
+        'bosatsu.comment':      hi_red,
+        'bosatsu.package.name': hi_orange,
+        'bosatsu.package.sep':  lo_orange,
+        'bosatsu.def':          hi_cyan,
+        'bosatsu.integer':      lo_orange,
+        'bosatsu.keyword':      lo_blue,
+        'bosatsu.operator':     hi_green,
+        'bosatsu.delimiter':    default,
+        'bosatsu.builtin':      lo_blue,
+        'bosatsu.predef':       hi_magenta,
+        'bosatsu.type':         hi_orange,
+        'bosatsu.string.start': lo_orange,
+        'bosatsu.string.data':  hi_orange,
+        'bosatsu.string.end':   lo_orange,
+        'bosatsu.unknown':      ('default', 'magenta202'),
+
+    }
+
+    def __init__(self, w):
+        mode.Fundamental.__init__(self, w)
+        self.add_bindings('close-paren', (')',))
+        self.add_bindings('close-brace', ('}',))
+        self.add_bindings('close-bracket', (']',))
+
+install = Bosatsu.install