~singpolyma/dhall-ruby

ref: b730651e6b3b37087c71978b9665854114ef8dc6 dhall-ruby/lib/dhall/builtins.rb -rw-r--r-- 5.1 KiB
b730651eStephen Paul Weber All beta normalization except for functions 3 years ago
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
# frozen_string_literal: true

require "dhall/ast"

module Dhall
	class Builtin < Expression
		def ==(other)
			self.class == other.class
		end

		def call(*args)
			# Do not auto-normalize builtins to avoid recursion loop
			args.reduce(self) do |f, arg|
				Application.new(function: f, arguments: [arg])
			end
		end
	end

	module Builtins
		# rubocop:disable Style/ClassAndModuleCamelCase

		class Double_show < Builtin
			def call(arg)
				if arg.is_a?(Double)
					Text.new(value: "\"#{arg.to_s}\"")
				else
					super
				end
			end
		end

		class Integer_show < Builtin
			def call(arg)
				if arg.is_a?(Integer)
					Text.new(value: "\"#{arg.to_s}\"")
				else
					super
				end
			end
		end

		class Integer_toDouble < Builtin
			def call(arg)
				if arg.is_a?(Integer)
					Double.new(value: arg.value.to_f)
				else
					super
				end
			end
		end

		class Natural_build < Builtin
			def fusion(arg, *bogus)
				if bogus.empty? &&
				   arg.is_a?(Application) &&
				   arg.function == Natural_fold.new &&
				   arg.arguments.length == 1
					arg.arguments.first
				else
					super
				end
			end

			def call(arg)
				arg.call(
					Variable.new(name: "Natural"),
					Function.new(
						var:  "_",
						type: Variable.new(name: "Natural"),
						body: Operator::Plus.new(
							lhs: Variable.new(name: "_"),
							rhs: Natural.new(value: 1)
						)
					),
					Natural.new(value: 0)
				)
			end
		end

		class Natural_even < Builtin
			def call(nat)
				if nat.is_a?(Natural)
					Bool.new(value: nat.even?)
				else
					super
				end
			end
		end

		class Natural_fold < Builtin
			def initialize(nat=nil, type=nil, f=nil)
				@nat = nat
				@type = type
				@f = f
			end

			def call(arg)
				if @nat.nil? && arg.is_a?(Natural)
					Natural_fold.new(arg)
				elsif !@nat.nil? && @type.nil?
					Natural_fold.new(@nat, arg)
				elsif !@nat.nil? && !@type.nil? && @f.nil?
					Natural_fold.new(@nat, @type, arg)
				elsif !@nat.nil? && !@type.nil? && !@f.nil?
					if @nat.zero?
						arg.normalize
					else
						@f.call(Natural_fold.new(@nat.pred, @type, @f).call(arg))
					end
				else
					super
				end
			end
		end

		class Natural_isZero < Builtin
			def call(nat)
				if nat.is_a?(Natural)
					Bool.new(value: nat.zero?)
				else
					super
				end
			end
		end

		class Natural_odd < Builtin
			def call(nat)
				if nat.is_a?(Natural)
					Bool.new(value: nat.odd?)
				else
					super
				end
			end
		end

		class Natural_show < Builtin
			def call(nat)
				if nat.is_a?(Natural)
					Text.new(value: nat.to_s)
				else
					super
				end
			end
		end

		class Natural_toInteger < Builtin
			def call(nat)
				if nat.is_a?(Natural)
					Integer.new(value: nat.value)
				else
					super
				end
			end
		end

		class List_build < Builtin
			def fusion(*args)
				_, arg, = args
				if arg.is_a?(Application) &&
				   arg.function.is_a?(Application) &&
				   arg.function.function == List_fold.new &&
				   arg.arguments.length == 1
					arg.arguments.first
				else
					super
				end
			end
		end

		class List_fold < Builtin
			def initialize(ltype=nil, list=nil, ztype=nil, f=nil)
				@ltype = ltype
				@list = list
				@ztype = ztype
				@f = f
			end

			def call(arg)
				if @ltype.nil?
					List_fold.new(arg)
				elsif @list.nil?
					List_fold.new(@ltype, arg)
				elsif @ztype.nil?
					List_fold.new(@ltype, @list, arg)
				elsif @f.nil?
					List_fold.new(@ltype, @list, @ztype, arg)
				else
					@list.reduce(arg, &@f).normalize
				end
			end
		end

		class List_head < Builtin
			def call(arg)
				if arg.is_a?(List)
					arg.first
				else
					super
				end
			end
		end

		class List_indexed < Builtin
			def call(arg)
				if arg.is_a?(List)
					arg.map(type: RecordType.new(
						"index" => Variable.new(name: "Natural"),
						"value" => arg.type
					)) do |x, idx|
						Record.new(
							"index" => Natural.new(value: idx),
							"value" => x
						)
					end
				else
					super
				end
			end
		end

		class List_last < Builtin
			def call(arg)
				if arg.is_a?(List)
					arg.last
				else
					super
				end
			end
		end

		class List_length < Builtin
			def call(arg)
				if arg.is_a?(List)
					Natural.new(value: arg.length)
				else
					super
				end
			end
		end

		class List_reverse < Builtin
			def call(arg)
				if arg.is_a?(List)
					arg.reverse
				else
					super
				end
			end
		end

		class Optional_build < Builtin
			def fusion(*args)
				_, arg, = args
				if arg.is_a?(Application) &&
				   arg.function.is_a?(Application) &&
				   arg.function.function == Optional_fold.new &&
				   arg.arguments.length == 1
					arg.arguments.first
				else
					super
				end
			end
		end

		class Optional_fold < Builtin
		end

		class Text_show < Builtin
			ENCODE = (Hash.new { |_, x| "\\u%04x" % x.ord }).merge(
				"\"" => "\\\"",
				"\\" => "\\\\",
				"\b" => "\\b",
				"\f" => "\\f",
				"\n" => "\\n",
				"\r" => "\\r",
				"\t" => "\\t"
			)

			def call(arg)
				if arg.is_a?(Text)
					Text.new(
						value: "\"#{arg.value.gsub(
							/["\$\\\b\f\n\r\t\u0000-\u001F]/,
							&ENCODE
						)}\""
					)
				else
					super
				end
			end
		end

		ALL = Hash[constants.map { |c| [c.to_s.tr("_", "/"), const_get(c)] }]
	end
end