Parse some code.

tools/cmake2meson.py

@@ -14,6 +14,66 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import sys, os
+import re
+
+class Lexer:
+    def __init__(self):
+        self.token_specification = [
+            # Need to be sorted longest to shortest.
+            ('ignore', re.compile(r'[ \t]')),
+            ('id', re.compile('[_0-9a-z/A-Z.]+')),
+            ('eol', re.compile(r'\n')),
+            ('comment', re.compile(r'\#.*')),
+            ('lparen', re.compile(r'\(')),
+            ('rparen', re.compile(r'\)')),
+            ('string', re.compile('"[^"]*?"')),
+        ]
+
+    def lex(self, code):
+        lineno = 1
+        line_start = 0
+        loc = 0;
+        col = 0
+        while(loc < len(code)):
+            matched = False
+            value = None
+            for (tid, reg) in self.token_specification:
+                mo = reg.match(code, loc)
+                if mo:
+                    curline = lineno
+                    col = mo.start()-line_start
+                    matched = True
+                    loc = mo.end()
+                    match_text = mo.group()
+                    if tid == 'ignore' or tid == 'comment':
+                        pass
+                    elif tid == 'lparen':
+                        yield('lparen')
+                    elif tid == 'rparen':
+                        yield('rparen')
+                    elif tid == 'string':
+                        yield('String: ' + match_text[1:-1])
+                    elif tid == 'id':
+                        yield('Id: ' + match_text)
+                    elif tid == 'eol':
+                        yield('eol')
+                    else:
+                        raise RuntimeError('Wharrgarbl')
+                    break
+            if not matched:
+                raise RuntimeError('Lexer got confused %d %d' % (lineno, col))
+
+def convert(cmake_root):
+    cfile = os.path.join(cmake_root, 'CMakeLists.txt')
+    cmakecode = open(cfile).read()
+    l = Lexer()
+    for t in l.lex(cmakecode):
+        print(t)
+
 
 if __name__ == '__main__':
-    pass
+    if len(sys.argv) != 2:
+        print(sys.argv[0], '<CMake project root>')
+    convert(sys.argv[1])
+