#copyright ReportLab Inc. 2000

#see license.txt for license details

#history http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/reportlab/lib/yaml.py?cvsroot=reportlab

# parses "Yet Another Markup Language" into a list of tuples.

# Each tuple says what the data is e.g.

# ('Paragraph', 'Heading1', 'Why Reportlab Rules')

# and the pattern depends on type.

"""

.h1 Welcome to YAML!

YAML is "Yet Another Markup Language" - a markup language

which is easier to type in than XML, yet gives us a

reasonable selection of formats.

The general rule is that if a line begins with a '.',

it requires special processing. Otherwise lines

are concatenated to paragraphs, and blank lines

If the line ".foo bar bletch" is encountered,

it immediately ends and writes out any current

paragraph.

It then looks for a parser method called 'foo';

if found, it is called with arguments (bar, bletch).

If this is not found, it assumes that 'foo' is a

paragraph style, and the text for the first line

of the paragraph is 'bar bletch'.  It would be

up to the formatter to decide whether on not 'foo'

was a valid paragraph.

Special commands understood at present are:

dot image filename

- adds the image to the document

dot beginPre Code

- begins a Preformatted object in style 'Code'

dot endPre

- ends a preformatted object.

"""

import sys

import string

#modes:

PLAIN = 1

PREFORMATTED = 2

BULLETCHAR = '\267'  # assumes font Symbol, but works on all platforms

class BaseParser:

    """"Simplest possible parser with only the most basic options.

    This defines the line-handling abilities and basic mechanism.

    The class YAMLParser includes capabilities for a fairly rich

    story."""

    def __init__(self):

        self.reset()

    def reset(self):

        self._lineNo = 0

        self._style = 'Normal'  # the default

        self._results = []

        self._buf = []

        self._mode = PLAIN

    def parseFile(self, filename):

        #returns list of objects

        data = open(filename, 'r').readlines()

        for line in data:

            #strip trailing newlines

            self.readLine(line[:-1])

        self.endPara()

        return self._results

    def parseText(self, textBlock):

        "Parses the a possible multi-line text block"

        lines = string.split(textBlock, '\n')

        for line in lines:

            self.readLine(line)

        self.endPara()

        return self._results

        #this is the inner loop

        self._lineNo = self._lineNo + 1

        stripped = string.lstrip(line)

        if len(stripped) == 0:

            if self._mode == PLAIN:

                self.endPara()

            else:  #preformatted, append it

                self._buf.append(line)

        elif line[0]=='.':

            # we have a command of some kind

            self.endPara()

            words = string.split(stripped[1:])

            cmd, args = words[0], words[1:]

            #is it a parser method?

            if hasattr(self.__class__, cmd):

                method = eval('self.'+cmd)

                #this was very bad; any type error in the method was hidden

                #we have to hack the traceback

                try:

                    apply(method, tuple(args))

                except TypeError, err:

                    sys.stderr.write("Parser method: apply(%s,%s) %s at line %d\n" % (cmd, tuple(args), err, self._lineNo))

                    raise

            else:

                # assume it is a paragraph style -

                # becomes the formatter's problem

                self.endPara()  #end the last one

                words = string.split(stripped, ' ', 1)

                assert len(words)==2, "Style %s but no data at line %d" % (words[0], self._lineNo)

                (styletag, data) = words

                self._style = styletag[1:]

                self._buf.append(data)

        else:

            #we have data, add to para

    def endPara(self):

        #ends the current paragraph, or preformatted block

        text = string.join(self._buf, ' ')

        if text:

            if self._mode == PREFORMATTED:

                #item 3 is list of lines

                self._results.append(('PREFORMATTED', self._style,

                                 string.join(self._buf,'\n')))

            else:

                self._results.append(('PARAGRAPH', self._style, text))

        self._buf = []

        self._style = 'Normal'

    def beginPre(self, stylename):

        self._mode = PREFORMATTED

        self._style = stylename

    def endPre(self):

        self.endPara()

        self._mode = PLAIN

    def image(self, filename):

        self.endPara()

        self._results.append(('IMAGE', filename))

class Parser(BaseParser):

    """This adds a basic set of "story" components compatible with HTML & PDF.

    Images, spaces"""

    def vSpace(self, points):

        """Inserts a vertical spacer"""

        self._results.append(('VSpace', points))

    def pageBreak(self):

        """Inserts a frame break"""

        self._results.append(('PageBreak','blah'))  # must be a tuple

    def custom(self, moduleName, funcName):

        """Goes and gets the Python object and adds it to the story"""

        self.endPara()

        self._results.append(('Custom',moduleName, funcName))

    def nextPageTemplate(self, templateName):

        self._results.append(('NextPageTemplate',templateName))

def parseFile(filename):

    p = Parser()

    return p.parseFile(filename)

def parseText(textBlock):

    p = Parser()

    return p.parseText(textBlock)

if __name__=='__main__': #NORUNTESTS

    if len(sys.argv) <> 2:

        results = parseText(__doc__)

    else:

        results = parseFile(sys.argv[1])

    import pprint