| 1 | """AST for ASDL.
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| 2 |
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| 3 | (Not self-hosted!)
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| 4 | """
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| 5 | from __future__ import print_function
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| 6 |
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| 7 | import cStringIO
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| 8 |
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| 9 | from typing import List
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| 10 |
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| 11 | # The following classes are the AST for the ASDL schema, i.e. the "meta-AST".
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| 12 | # See the EBNF at the top of the file to understand the logical connection
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| 13 | # between the various node types.
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| 14 |
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| 15 |
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| 16 | class AST(object):
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| 17 |
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| 18 | def Print(self, f, indent):
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| 19 | raise NotImplementedError()
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| 20 |
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| 21 | def __str__(self):
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| 22 | f = cStringIO.StringIO()
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| 23 | self.Print(f, 0)
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| 24 | return f.getvalue()
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| 25 |
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| 26 |
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| 27 | class Use(AST):
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| 28 |
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| 29 | def __init__(self, module_parts, type_names):
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| 30 | self.module_parts = module_parts
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| 31 | self.type_names = type_names
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| 32 |
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| 33 | def Print(self, f, indent):
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| 34 | ind = indent * ' '
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| 35 | f.write('%sUse %s {\n' % (ind, ' '.join(self.module_parts)))
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| 36 | f.write(' %s%s\n' % (ind, ', '.join(t for t in self.type_names)))
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| 37 | f.write('%s}\n' % ind)
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| 38 |
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| 39 |
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| 40 | class Module(AST):
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| 41 |
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| 42 | def __init__(self, name, uses, dfns):
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| 43 | self.name = name
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| 44 | self.uses = uses
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| 45 | self.dfns = dfns
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| 46 |
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| 47 | def Print(self, f, indent):
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| 48 | ind = indent * ' '
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| 49 | f.write('%sModule %s {\n' % (ind, self.name))
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| 50 |
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| 51 | for u in self.uses:
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| 52 | u.Print(f, indent + 1)
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| 53 | f.write('\n')
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| 54 |
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| 55 | for d in self.dfns:
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| 56 | d.Print(f, indent + 1)
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| 57 | f.write('\n')
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| 58 | f.write('%s}\n' % ind)
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| 59 |
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| 60 |
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| 61 | class TypeDecl(AST):
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| 62 | """A binding of name to a Sum or Product type."""
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| 63 |
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| 64 | def __init__(self, name, value):
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| 65 | self.name = name # type: str
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| 66 | self.value = value # type: AST
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| 67 |
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| 68 | def Print(self, f, indent):
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| 69 | ind = indent * ' '
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| 70 | f.write('%sType %s {\n' % (ind, self.name))
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| 71 | self.value.Print(f, indent + 1)
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| 72 | f.write('%s}\n' % ind)
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| 73 |
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| 74 |
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| 75 | class NamedType(AST):
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| 76 | """Int, string are resolved to a Primitive type 'Point' can be resolved to
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| 77 | CompoundSum instance, etc."""
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| 78 |
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| 79 | def __init__(self, name):
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| 80 | # type: (str) -> None
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| 81 | self.name = name
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| 82 |
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| 83 | # Mutated by _ResolveModule / _ResolveType
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| 84 | self.resolved = None
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| 85 |
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| 86 | def Print(self, f, indent):
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| 87 | """Printed on one line."""
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| 88 | f.write('NamedType %s' % (self.name)) # printed after field
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| 89 | f.write(' (%r)' % self.resolved)
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| 90 |
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| 91 | def IsOptional(self):
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| 92 | return False
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| 93 |
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| 94 | def IsList(self):
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| 95 | return False
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| 96 |
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| 97 | def IsDict(self):
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| 98 | return False
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| 99 |
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| 100 |
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| 101 | class ParameterizedType(AST):
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| 102 | """A parameterized type expression, e.g. the type of a field.
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| 103 |
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| 104 | e.g. Dict[string, int] Dict[int, array[string]]
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| 105 |
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| 106 | self.children is empty if it's a leaf.
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| 107 |
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| 108 | Note:
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| 109 |
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| 110 | string* <=> array[string]
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| 111 | mytype? <=> maybe[mytype]
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| 112 | """
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| 113 |
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| 114 | def __init__(self, type_name, children):
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| 115 | self.type_name = type_name # type: str
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| 116 | self.children = children # type: List[AST]
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| 117 |
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| 118 | def Print(self, f, indent):
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| 119 | """Printed on one line."""
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| 120 | f.write('%s' % (self.type_name)) # printed after field
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| 121 | if self.children:
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| 122 | f.write(' [ ')
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| 123 | for i, child in enumerate(self.children):
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| 124 | if i != 0:
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| 125 | f.write(', ')
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| 126 | child.Print(f, indent + 1)
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| 127 | f.write(' ]')
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| 128 |
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| 129 | def IsOptional(self):
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| 130 | return self.type_name == 'Optional'
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| 131 |
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| 132 | def IsList(self):
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| 133 | if self.type_name == 'List':
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| 134 | return True
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| 135 | if self.type_name == 'Optional':
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| 136 | return self.children[0].IsList()
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| 137 | return False
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| 138 |
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| 139 | def IsDict(self):
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| 140 | if self.type_name == 'Dict':
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| 141 | return True
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| 142 | if self.type_name == 'Optional':
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| 143 | return self.children[0].IsDict()
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| 144 | return False
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| 145 |
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| 146 |
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| 147 | class Field(AST):
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| 148 |
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| 149 | def __init__(self, typ, name):
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| 150 | # type: (AST, str) -> None
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| 151 | self.typ = typ # type expression
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| 152 | self.name = name # variable name
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| 153 |
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| 154 | def Print(self, f, indent):
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| 155 | ind = indent * ' '
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| 156 | f.write('%sField %r ' % (ind, self.name))
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| 157 | self.typ.Print(f, indent)
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| 158 | f.write('\n')
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| 159 |
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| 160 |
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| 161 | class _CompoundAST(AST):
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| 162 | """Either a Product or Constructor.
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| 163 |
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| 164 | encode.py and format.py need a reflection API.
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| 165 | """
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| 166 |
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| 167 | def __init__(self, fields):
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| 168 | self.fields = fields or []
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| 169 |
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| 170 |
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| 171 | class Constructor(_CompoundAST):
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| 172 |
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| 173 | def __init__(self, name, shared_type=None, fields=None):
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| 174 | _CompoundAST.__init__(self, fields)
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| 175 | self.name = name
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| 176 | self.shared_type = shared_type # for DoubleQuoted %DoubleQuoted
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| 177 |
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| 178 | def Print(self, f, indent):
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| 179 | ind = indent * ' '
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| 180 | f.write('%sConstructor %s' % (ind, self.name))
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| 181 | if self.shared_type:
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| 182 | f.write(' %%%s' % self.shared_type)
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| 183 |
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| 184 | if self.fields:
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| 185 | f.write(' {\n')
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| 186 | for field in self.fields:
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| 187 | field.Print(f, indent + 1)
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| 188 | f.write('%s}' % ind)
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| 189 |
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| 190 | f.write('\n')
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| 191 |
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| 192 |
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| 193 | class Sum(AST):
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| 194 |
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| 195 | def __init__(self, types, generate=None):
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| 196 | self.types = types # type: List[Constructor]
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| 197 | self.generate = generate or []
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| 198 |
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| 199 | def Print(self, f, indent):
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| 200 | ind = indent * ' '
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| 201 | f.write('%sSum {\n' % ind)
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| 202 | for t in self.types:
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| 203 | t.Print(f, indent + 1)
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| 204 | if self.generate:
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| 205 | f.write('%s generate %s\n' % (ind, self.generate))
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| 206 | f.write('%s}\n' % ind)
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| 207 |
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| 208 |
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| 209 | class SimpleSum(Sum):
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| 210 | pass
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| 211 |
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| 212 |
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| 213 | class Product(_CompoundAST):
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| 214 |
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| 215 | def __init__(self, fields):
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| 216 | _CompoundAST.__init__(self, fields)
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| 217 |
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| 218 | def Print(self, f, indent):
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| 219 | ind = indent * ' '
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| 220 | f.write('%sProduct {\n' % ind)
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| 221 | for field in self.fields:
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| 222 | field.Print(f, indent + 1)
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| 223 | f.write('%s}\n' % ind)
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| 224 |
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| 225 |
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| 226 | #
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| 227 | # Helpers
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| 228 | #
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| 229 |
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| 230 |
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| 231 | def TypeNameHeuristic(t):
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| 232 | # type: (str) -> str
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| 233 | """For 'use'.
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| 234 |
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| 235 | We don't parse the imported file, so we have a heuristic based on
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| 236 | the name! e.g. re_t or BraceGroup
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| 237 | """
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| 238 | return '%s_t' % t if t[0].islower() else t
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