forked from mirrors/gecko-dev
		
	This was done with |mach vendor python| followed by a manual backout of changes to unrelated packages. Differential Revision: https://phabricator.services.mozilla.com/D5532 --HG-- extra : moz-landing-system : lando
		
			
				
	
	
		
			354 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			354 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
from __future__ import absolute_import, print_function, unicode_literals
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import re
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import json as json
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from .shared import JSONTemplateError, TemplateError, DeleteMarker, string, to_str
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from . import shared
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from .interpreter import ExpressionEvaluator
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from .six import viewitems
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import functools
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operators = {}
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IDENTIFIER_RE = re.compile(r'[a-zA-Z_][a-zA-Z0-9_]*$')
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def operator(name):
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    def wrap(fn):
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        operators[name] = fn
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        return fn
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    return wrap
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def evaluateExpression(expr, context):
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    evaluator = ExpressionEvaluator(context)
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    return evaluator.parse(expr)
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_interpolation_start_re = re.compile(r'\$?\${')
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def interpolate(string, context):
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    mo = _interpolation_start_re.search(string)
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    if not mo:
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        return string
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    result = []
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    evaluator = ExpressionEvaluator(context)
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    while True:
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        result.append(string[:mo.start()])
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        if mo.group() != '$${':
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            string = string[mo.end():]
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            parsed, offset = evaluator.parseUntilTerminator(string, '}')
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            if isinstance(parsed, (list, dict)):
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                raise TemplateError(
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                    "interpolation of '{}' produced an array or object".format(string[:offset]))
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            if to_str(parsed) == "null":
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                result.append("")
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            else:
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                result.append(to_str(parsed))
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            string = string[offset + 1:]
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        else:  # found `$${`
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            result.append('${')
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            string = string[mo.end():]
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        mo = _interpolation_start_re.search(string)
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        if not mo:
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            result.append(string)
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            break
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    return ''.join(result)
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def checkUndefinedProperties(template, allowed):
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    unknownKeys = []
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    combined = "|".join(allowed) + "$"
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    unknownKeys = [key for key in sorted(template)
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                   if not re.match(combined, key)]
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    if unknownKeys:
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        raise TemplateError(allowed[0].replace('\\', '') +
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                            " has undefined properties: " + " ".join(unknownKeys))
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@operator('$eval')
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def eval(template, context):
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    checkUndefinedProperties(template, ['\$eval'])
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    if not isinstance(template['$eval'], string):
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        raise TemplateError("$eval must be given a string expression")
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    return evaluateExpression(template['$eval'], context)
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@operator('$flatten')
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def flatten(template, context):
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    checkUndefinedProperties(template, ['\$flatten'])
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    value = renderValue(template['$flatten'], context)
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    if not isinstance(value, list):
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        raise TemplateError('$flatten value must evaluate to an array')
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    def gen():
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        for e in value:
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            if isinstance(e, list):
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                for e2 in e:
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                    yield e2
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            else:
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                yield e
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    return list(gen())
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@operator('$flattenDeep')
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def flattenDeep(template, context):
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    checkUndefinedProperties(template, ['\$flattenDeep'])
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    value = renderValue(template['$flattenDeep'], context)
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    if not isinstance(value, list):
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        raise TemplateError('$flattenDeep value must evaluate to an array')
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    def gen(value):
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        if isinstance(value, list):
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            for e in value:
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                for sub in gen(e):
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                    yield sub
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        else:
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            yield value
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    return list(gen(value))
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@operator('$fromNow')
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def fromNow(template, context):
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    checkUndefinedProperties(template, ['\$fromNow', 'from'])
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    offset = renderValue(template['$fromNow'], context)
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    reference = renderValue(
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        template['from'], context) if 'from' in template else context.get('now')
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    if not isinstance(offset, string):
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        raise TemplateError("$fromNow expects a string")
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    return shared.fromNow(offset, reference)
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@operator('$if')
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def ifConstruct(template, context):
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    checkUndefinedProperties(template, ['\$if', 'then', 'else'])
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    condition = evaluateExpression(template['$if'], context)
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    try:
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        if condition:
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            rv = template['then']
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        else:
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            rv = template['else']
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    except KeyError:
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        return DeleteMarker
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    return renderValue(rv, context)
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@operator('$json')
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def jsonConstruct(template, context):
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    checkUndefinedProperties(template, ['\$json'])
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    value = renderValue(template['$json'], context)
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    return json.dumps(value, separators=(',', ':'), sort_keys=True, ensure_ascii=False)
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@operator('$let')
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def let(template, context):
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    checkUndefinedProperties(template, ['\$let', 'in'])
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    if not isinstance(template['$let'], dict):
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        raise TemplateError("$let value must be an object")
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    subcontext = context.copy()
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    for k, v in template['$let'].items():
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        if not IDENTIFIER_RE.match(k):
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            raise TemplateError('top level keys of $let must follow /[a-zA-Z_][a-zA-Z0-9_]*/')
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        subcontext[k] = renderValue(v, context)
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    try:
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        in_expression = template['in']
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    except KeyError:
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        raise TemplateError("$let operator requires an `in` clause")
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    return renderValue(in_expression, subcontext)
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@operator('$map')
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def map(template, context):
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    EACH_RE = 'each\([a-zA-Z_][a-zA-Z0-9_]*\)'
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    checkUndefinedProperties(template, ['\$map', EACH_RE])
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    value = renderValue(template['$map'], context)
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    if not isinstance(value, list) and not isinstance(value, dict):
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        raise TemplateError("$map value must evaluate to an array or object")
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    is_obj = isinstance(value, dict)
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    each_keys = [k for k in template if k.startswith('each(')]
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    if len(each_keys) != 1:
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        raise TemplateError(
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            "$map requires exactly one other property, each(..)")
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    each_key = each_keys[0]
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    each_var = each_key[5:-1]
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    each_template = template[each_key]
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    def gen(val):
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        subcontext = context.copy()
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        for elt in val:
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            subcontext[each_var] = elt
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            elt = renderValue(each_template, subcontext)
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            if elt is not DeleteMarker:
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                yield elt
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    if is_obj:
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        value = [{'key': v[0], 'val': v[1]} for v in value.items()]
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        v = dict()
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        for e in gen(value):
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            if not isinstance(e, dict):
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                raise TemplateError(
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                    "$map on objects expects {0} to evaluate to an object".format(each_key))
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            v.update(e)
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        return v
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    else:
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        return list(gen(value))
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@operator('$match')
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def matchConstruct(template, context):
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    checkUndefinedProperties(template, ['\$match'])
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    if not isinstance(template['$match'], dict):
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        raise TemplateError("$match can evaluate objects only")
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    result = []
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    for condition in template['$match']:
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        if evaluateExpression(condition, context):
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            result.append(renderValue(template['$match'][condition], context))
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    return result
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@operator('$merge')
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def merge(template, context):
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    checkUndefinedProperties(template, ['\$merge'])
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    value = renderValue(template['$merge'], context)
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    if not isinstance(value, list) or not all(isinstance(e, dict) for e in value):
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        raise TemplateError(
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            "$merge value must evaluate to an array of objects")
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    v = dict()
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    for e in value:
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        v.update(e)
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    return v
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@operator('$mergeDeep')
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def merge(template, context):
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    checkUndefinedProperties(template, ['\$mergeDeep'])
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    value = renderValue(template['$mergeDeep'], context)
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    if not isinstance(value, list) or not all(isinstance(e, dict) for e in value):
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        raise TemplateError(
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            "$mergeDeep value must evaluate to an array of objects")
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    def merge(l, r):
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        if isinstance(l, list) and isinstance(r, list):
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            return l + r
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        if isinstance(l, dict) and isinstance(r, dict):
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            res = l.copy()
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            for k, v in viewitems(r):
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                if k in l:
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                    res[k] = merge(l[k], v)
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                else:
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                    res[k] = v
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            return res
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        return r
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    if len(value) == 0:
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        return {}
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    return functools.reduce(merge, value[1:], value[0])
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@operator('$reverse')
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def reverse(template, context):
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    checkUndefinedProperties(template, ['\$reverse'])
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    value = renderValue(template['$reverse'], context)
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    if not isinstance(value, list):
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        raise TemplateError("$reverse value must evaluate to an array of objects")
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    return list(reversed(value))
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@operator('$sort')
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def sort(template, context):
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    BY_RE = 'by\([a-zA-Z_][a-zA-Z0-9_]*\)'
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    checkUndefinedProperties(template, ['\$sort', BY_RE])
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    value = renderValue(template['$sort'], context)
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    if not isinstance(value, list):
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        raise TemplateError('$sorted values to be sorted must have the same type')
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    # handle by(..) if given, applying the schwartzian transform
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    by_keys = [k for k in template if k.startswith('by(')]
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    if len(by_keys) == 1:
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        by_key = by_keys[0]
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        by_var = by_key[3:-1]
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        by_expr = template[by_key]
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        def xform():
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            subcontext = context.copy()
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            for e in value:
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                subcontext[by_var] = e
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                yield evaluateExpression(by_expr, subcontext), e
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        to_sort = list(xform())
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    elif len(by_keys) == 0:
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        to_sort = [(e, e) for e in value]
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    else:
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        raise TemplateError('only one by(..) is allowed')
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    # check types
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    try:
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        eltype = type(to_sort[0][0])
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    except IndexError:
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        return []
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    if eltype in (list, dict, bool, type(None)):
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        raise TemplateError('$sorted values to be sorted must have the same type')
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    if not all(isinstance(e[0], eltype) for e in to_sort):
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        raise TemplateError('$sorted values to be sorted must have the same type')
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    # unzip the schwartzian transform
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    return list(e[1] for e in sorted(to_sort))
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def renderValue(template, context):
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    if isinstance(template, string):
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        return interpolate(template, context)
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    elif isinstance(template, dict):
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        matches = [k for k in template if k in operators]
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        if matches:
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            if len(matches) > 1:
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                raise TemplateError("only one operator allowed")
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            return operators[matches[0]](template, context)
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        def updated():
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            for k, v in viewitems(template):
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                if k.startswith('$$'):
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                    k = k[1:]
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                elif k.startswith('$') and IDENTIFIER_RE.match(k[1:]):
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                    raise TemplateError(
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                        '$<identifier> is reserved; ues $$<identifier>')
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                else:
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                    k = interpolate(k, context)
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                try:
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                    v = renderValue(v, context)
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                except JSONTemplateError as e:
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                    if IDENTIFIER_RE.match(k):
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                        e.add_location('.{}'.format(k))
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                    else:
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                        e.add_location('[{}]'.format(json.dumps(k)))
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                    raise
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                if v is not DeleteMarker:
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                    yield k, v
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        return dict(updated())
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    elif isinstance(template, list):
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        def updated():
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            for i, e in enumerate(template):
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                try:
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                    v = renderValue(e, context)
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                    if v is not DeleteMarker:
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                        yield v
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                except JSONTemplateError as e:
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                    e.add_location('[{}]'.format(i))
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                    raise
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        return list(updated())
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    else:
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        return template
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