Implement BlockParser

1 files changed, 111 insertions, 1 deletions

diff --git a/yarnlib/block_parser.py b/yarnlib/block_parser.py
index 8fd87d2..09a7a22 100644
--- a/yarnlib/block_parser.py
+++ b/yarnlib/block_parser.py
@@ -16,6 +16,116 @@
 # =*= License: GPL-3+ =*=
 
 
+import yarnlib
+
+
+# Parse a sequence of textual blocks into Story and Implementation
+# objects, and their constituent objects.
+
 class BlockParser(object):
 
-    pass
+    def __init__(self):
+        self.stories = []
+        self.implementations = []
+        self.line_parsers = {
+            'STORY': self.parse_story,
+            'GIVEN': self.parse_given,
+            'WHEN': self.parse_when,
+            'THEN': self.parse_then,
+            'FINALLY': self.parse_finally,
+            'AND': self.parse_and,
+            'IMPLEMENTS': self.parse_implementing,
+        }
+
+    def parse_blocks(self, blocks):
+        while blocks:
+            blocks = self.parse_one(blocks)
+
+    def parse_one(self, blocks):
+        assert blocks
+        block = blocks[0]
+        assert block
+        t = block.split('\n', 1)
+        assert len(t) in [1,2]
+        if len(t) == 1:
+            line1 = block
+            block = ''
+        else:
+            line1, block = t
+        if block:
+            blocks[0] = block
+        else:
+            del blocks[0]
+
+        words = line1.split()
+        if not words:
+            return blocks
+        rest = ' '.join(words[1:])
+
+        for keyword in self.line_parsers:
+            if words[0] == keyword:
+                return self.line_parsers[keyword](rest, blocks)
+
+        raise StoryTestSyntaxError("Syntax error: unknown step: %s" % line1)
+
+    def parse_story(self, line, blocks):
+        self.stories.append(yarnlib.Story(line))
+        return blocks
+
+    def parse_simple(self, what, line, blocks):
+        if not self.stories:
+            raise StoryTestSyntaxError('Syntax errror: %s before STORY' % what)
+        step = yarnlib.StoryStep(what, line)
+        self.stories[-1].steps.append(step)
+        return blocks
+
+    def parse_given(self, line, blocks):
+        return self.parse_simple('GIVEN', line, blocks)
+
+    def parse_when(self, line, blocks):
+        return self.parse_simple('WHEN', line, blocks)
+
+    def parse_then(self, line, blocks):
+        return self.parse_simple('THEN', line, blocks)
+
+    def parse_finally(self, line, blocks):
+        return self.parse_simple('FINALLY', line, blocks)
+
+    def parse_and(self, line, blocks):
+        if not self.stories:
+            raise StoryTestSyntaxError('Syntax errror: AND before STORY')
+        story = self.stories[-1]
+        if not story.steps:
+            raise StoryTestSyntaxError(
+                'Syntax errror: AND before what it would continue')
+        step = story.steps[-1]
+        assert step.what in self.line_parsers
+        return self.line_parsers[step.what](line, blocks)
+
+    def parse_implementing(self, line, blocks):
+        words = line.split()
+        if len(words) < 2:
+            raise StoryTestSyntaxError(
+                'Syntax error: IMPLEMENTING must have what and regexp')
+        what = words[0]
+        regexp = ' '.join(words[1:])
+        if blocks:
+            block = blocks[0]
+            shell = []
+            rest = []
+            for block_line in block.splitlines():
+                if rest or block_line.startswith('IMPLEMENTS'):
+                    rest.append(block_line)
+                else:
+                    shell.append(block_line)
+            shell = '\n'.join(shell)
+            if rest:
+                blocks[0] = '\n'.join(rest)
+            else:
+                del blocks[0]
+        else:
+            shell = ''
+        implementation = yarnlib.Implementation(what, regexp, shell)
+        self.implementations.append(implementation)
+        return blocks
+