templates.go

Documentation: cuelang.org/go/encoding/gocode

     1  // Copyright 2019 CUE Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gocode
    16  
    17  import (
    18  	"text/template"
    19  )
    20  
    21  // Inputs:
    22  // .pkgName  the Go package name
    23  var headerCode = template.Must(template.New("header").Parse(
    24  	`// Code generated by gocode.Generate; DO NOT EDIT.
    25  
    26  package {{.pkgName}}
    27  
    28  import (
    29  	"fmt"
    30  
    31  	"cuelang.org/go/cue"
    32  	"cuelang.org/go/encoding/gocode/gocodec"
    33  	_ "cuelang.org/go/pkg"
    34  )
    35  
    36  `))
    37  
    38  // Inputs:
    39  // .prefix 	  prefix to all generated variable names
    40  // .cueName   name of the top-level CUE value
    41  // .goType    Go type of the receiver or argument
    42  // .zero      zero value of the Go type; nil indicates no value
    43  // .validate  name of the validate function; "" means no validate
    44  // .complete  name of the complete function; "" means no complete
    45  var stubCode = template.Must(template.New("type").Parse(`
    46  var {{.prefix}}val{{.cueName}} = {{.prefix}}Make("{{.cueName}}", {{.zero}})
    47  
    48  {{ $sig := .goType | printf "(x %s)" -}}
    49  {{if .validate}}
    50  // {{.validate}}{{if .func}}{{.cueName}}{{end}} validates x.
    51  func {{if .func}}{{.validate}}{{.cueName}}{{$sig}}
    52       {{- else -}}{{$sig}} {{.validate}}(){{end}} error {
    53  	return {{.prefix}}Codec.Validate({{.prefix}}val{{.cueName}}, x)
    54  }
    55  {{end}}
    56  {{if .complete}}
    57  // {{.complete}}{{if .func}}{{.cueName}}{{end}} completes x.
    58  func {{if .func}}{{.complete}}{{.cueName}}{{$sig}}
    59       {{- else -}}{{$sig}} {{.complete}}(){{end}} error {
    60  	return {{.prefix}}Codec.Complete({{.prefix}}val{{.cueName}}, x)
    61  }
    62  {{end}}
    63  `))
    64  
    65  // Inputs:
    66  // .prefix 	  prefix to all generated variable names
    67  // .runtime   the variable name of a user-supplied runtime, if any
    68  // .data      bytes obtained from Instance.MarshalBinary
    69  var loadCode = template.Must(template.New("load").Parse(`
    70  var {{.prefix}}Codec, {{.prefix}}Instance_, {{.prefix}}Value = func() (*gocodec.Codec, *cue.Instance, cue.Value) {
    71  	var r *cue.Runtime
    72  	r = {{if .runtime}}{{.runtime}}{{else}}&cue.Runtime{}{{end}}
    73  	instances, err := r.Unmarshal({{.prefix}}InstanceData)
    74  	if err != nil {
    75  		panic(err)
    76  	}
    77  	if len(instances) != 1 {
    78  		panic("expected encoding of exactly one instance")
    79  	}
    80  	return gocodec.New(r, nil), instances[0], instances[0].Value()
    81  }()
    82  
    83  // Deprecated: cue.Instance is deprecated. Use {{.prefix}}Value instead.
    84  var {{.prefix}}Instance = {{.prefix}}Instance_
    85  
    86  // {{.prefix}}Make is called in the init phase to initialize CUE values for
    87  // validation functions.
    88  func {{.prefix}}Make(name string, x interface{}) cue.Value {
    89  	f, err := {{.prefix}}Value.FieldByName(name, true)
    90  	if err != nil {
    91  		panic(fmt.Errorf("could not find type %q in instance", name))
    92  	}
    93  	v := f.Value
    94  	if x != nil {
    95  		w, err := {{.prefix}}Codec.ExtractType(x)
    96  		if err != nil {
    97  			panic(err)
    98  		}
    99  		v = v.Unify(w)
   100  	}
   101  	return v
   102  }
   103  
   104  // Data size: {{len .data}} bytes.
   105  var {{.prefix}}InstanceData = []byte({{printf "%+q" .data }})
   106  `))
   107
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