Code generator for TALInterpreter intermediate code.

lib/python/TAL/TALGenerator.py

+##############################################################################
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+# 7. Modifications are encouraged but must be packaged separately as
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+# Disclaimer
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+#   THIS SOFTWARE IS PROVIDED BY DIGITAL CREATIONS ``AS IS'' AND ANY
+#   EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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+#   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.
+# 
+# 
+# This software consists of contributions made by Digital Creations and
+# many individuals on behalf of Digital Creations.  Specific
+# attributions are listed in the accompanying credits file.
+# 
+##############################################################################
+"""
+Code generator for TALInterpreter intermediate code.
+"""
+
+import re
+import cgi
+
+from TALDefs import *
+
+class DummyCompiler:
+
+    def compile(self, expr):
+        return expr
+
+class TALGenerator:
+
+    def __init__(self, expressionCompiler=None):
+        if not expressionCompiler:
+            expressionCompiler = DummyCompiler()
+        self.expressionCompiler = expressionCompiler
+        self.program = []
+        self.macros = {}
+        self.stack = []
+
+    def compileExpression(self, expr):
+        return self.expressionCompiler.compile(expr)
+
+    def pushProgram(self):
+        self.stack.append(self.program)
+        self.program = []
+
+    def popProgram(self):
+        program = self.program
+        self.program = self.stack.pop()
+        return program
+
+    def emit(self, *instruction):
+        self.program.append(instruction)
+
+    def emitStartTag(self, name, attrlist):
+        self.program.append(("startTag", name, attrlist))
+
+    def emitEndTag(self, name):
+        if self.program and self.program[-1][0] == "startTag":
+            # Minimize empty element
+            self.program[-1] = ("startEndTag",) + self.program[-1][1:]
+        else:
+            self.program.append(("endTag", name))
+
+    def emitText(self, text):
+        self.program.append(("rawtext", cgi.escape(text)))
+
+    def emitDefines(self, defines):
+        for part in splitParts(defines):
+            m = re.match(
+                r"\s*(?:(global|local)\s+)?(%s)\s+(.*)" % NAME_RE, part)
+            if not m:
+                raise TALError("invalid z:define syntax: " + `part`)
+            scope, name, expr = m.group(1, 2, 3)
+            scope = scope or "local"
+            cexpr = self.compileExpression(expr)
+            if scope == "local":
+                self.emit("setLocal", name, cexpr)
+            else:
+                self.emit("setGlobal", name, cexpr)
+
+    def emitCondition(self, expr):
+        cexpr = self.compileExpression(expr)
+        program = self.popProgram()
+        self.emit("condition", cexpr, program)
+
+    def emitRepeat(self, arg):
+        m = re.match("\s*(%s)\s+(.*)" % NAME_RE, arg)
+        if not m:
+            raise TALError("invalid z:repeat syntax: " + `repeat`)
+        name, expr = m.group(1, 2)
+        cexpr = self.compileExpression(expr)
+        program = self.popProgram()
+        self.emit("loop", name, cexpr, program)
+
+    def emitSubstitution(self, arg, attrDict={}):
+        key, expr = parseSubstitution(arg)
+        if not key:
+            raise TALError("Bad syntax in z:insert/z:replace: " + `arg`)
+        cexpr = self.compileExpression(expr)
+        program = self.popProgram()
+        if key == "text":
+            self.emit("insertText", cexpr, program)
+        else:
+            assert key == "structure"
+            self.emit("insertStructure", cexpr, attrDict, program)
+        
+
+def test():
+    t = TALGenerator()
+    t.pushProgram()
+    t.emit("bar")
+    p = t.popProgram()
+    t.emit("foo", p)
+
+if __name__ == "__main__":
+    test()