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| 1 | +// Copyright 2021 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 cue |
| 16 | + |
| 17 | +import ( |
| 18 | + "bytes" |
| 19 | + "fmt" |
| 20 | + "math/big" |
| 21 | + |
| 22 | + "cuelang.org/go/cue/ast" |
| 23 | + "cuelang.org/go/cue/format" |
| 24 | + "cuelang.org/go/internal/core/export" |
| 25 | +) |
| 26 | + |
| 27 | +// TODO: |
| 28 | +// * allow '-' to strip outer curly braces? |
| 29 | +// - simplify output; can be used in combination with other flags |
| 30 | +// * advertise: |
| 31 | +// c like v, but print comments |
| 32 | +// a like c, but print attributes and package-local hidden fields as well |
| 33 | + |
| 34 | +// Format prints a CUE value. |
| 35 | +// |
| 36 | +// WARNING: |
| 37 | +// although we are narrowing down the semantics, the verbs and options |
| 38 | +// are still subject to change. this API is experimental although it is |
| 39 | +// likely getting close to the final design. |
| 40 | +// |
| 41 | +// It recognizes the following verbs: |
| 42 | +// |
| 43 | +// v print CUE value |
| 44 | +// |
| 45 | +// The verbs support the following flags: |
| 46 | +// # print as schema and include definitions. |
| 47 | +// The result is printed as a self-contained file, instead of an the |
| 48 | +// expression format. |
| 49 | +// + evaluate: resolve defaults and error on incomplete errors |
| 50 | +// |
| 51 | +// Indentation can be controlled as follows: |
| 52 | +// width indent the cue block by <width> tab stops (e.g. %2v) |
| 53 | +// precision convert tabs to <precision> spaces (e.g. %.2v), where |
| 54 | +// a value of 0 means no indentation or newlines (TODO). |
| 55 | +// |
| 56 | +// If the value kind corresponds to one of the following Go types, the |
| 57 | +// usual Go formatting verbs for that type can be used: |
| 58 | +// |
| 59 | +// Int: b,d,o,O,q,x,X |
| 60 | +// Float: f,e,E,g,G |
| 61 | +// String/Bytes: s,q,x,X |
| 62 | +// |
| 63 | +// The %v directive will be used if the type is not supported for that verb. |
| 64 | +// |
| 65 | +func (v Value) Format(state fmt.State, verb rune) { |
| 66 | + if v.v == nil { |
| 67 | + fmt.Fprint(state, "<nil>") |
| 68 | + return |
| 69 | + } |
| 70 | + |
| 71 | + switch verb { |
| 72 | + case 'a': |
| 73 | + formatCUE(state, v, true, true) |
| 74 | + case 'c': |
| 75 | + formatCUE(state, v, true, false) |
| 76 | + case 'v': |
| 77 | + formatCUE(state, v, false, false) |
| 78 | + |
| 79 | + case 'd', 'o', 'O', 'U': |
| 80 | + var i big.Int |
| 81 | + if _, err := v.Int(&i); err != nil { |
| 82 | + formatCUE(state, v, false, false) |
| 83 | + return |
| 84 | + } |
| 85 | + i.Format(state, verb) |
| 86 | + |
| 87 | + case 'f', 'e', 'E', 'g', 'G': |
| 88 | + d, err := v.Decimal() |
| 89 | + if err != nil { |
| 90 | + formatCUE(state, v, false, false) |
| 91 | + return |
| 92 | + } |
| 93 | + d.Format(state, verb) |
| 94 | + |
| 95 | + case 's', 'q': |
| 96 | + // TODO: this drops other formatting directives |
| 97 | + msg := "%s" |
| 98 | + if verb == 'q' { |
| 99 | + msg = "%q" |
| 100 | + } |
| 101 | + |
| 102 | + if b, err := v.Bytes(); err == nil { |
| 103 | + fmt.Fprintf(state, msg, b) |
| 104 | + } else { |
| 105 | + s := fmt.Sprintf("%+v", v) |
| 106 | + fmt.Fprintf(state, msg, s) |
| 107 | + } |
| 108 | + |
| 109 | + case 'x', 'X': |
| 110 | + switch v.Kind() { |
| 111 | + case StringKind, BytesKind: |
| 112 | + b, _ := v.Bytes() |
| 113 | + // TODO: this drops other formatting directives |
| 114 | + msg := "%x" |
| 115 | + if verb == 'X' { |
| 116 | + msg = "%X" |
| 117 | + } |
| 118 | + fmt.Fprintf(state, msg, b) |
| 119 | + |
| 120 | + case IntKind, NumberKind: |
| 121 | + var i big.Int |
| 122 | + _, _ = v.Int(&i) |
| 123 | + i.Format(state, verb) |
| 124 | + |
| 125 | + case FloatKind: |
| 126 | + dec, _ := v.Decimal() |
| 127 | + dec.Format(state, verb) |
| 128 | + |
| 129 | + default: |
| 130 | + formatCUE(state, v, false, false) |
| 131 | + } |
| 132 | + |
| 133 | + default: |
| 134 | + formatCUE(state, v, false, false) |
| 135 | + } |
| 136 | +} |
| 137 | + |
| 138 | +func formatCUE(state fmt.State, v Value, showDocs, showAll bool) { |
| 139 | + |
| 140 | + pkgPath := v.instance().ID() |
| 141 | + |
| 142 | + p := *export.Simplified |
| 143 | + |
| 144 | + isDef := false |
| 145 | + switch { |
| 146 | + case state.Flag('#'): |
| 147 | + isDef = true |
| 148 | + p = export.Profile{ |
| 149 | + ShowOptional: true, |
| 150 | + ShowDefinitions: true, |
| 151 | + ShowHidden: true, |
| 152 | + } |
| 153 | + |
| 154 | + case state.Flag('+'): |
| 155 | + p = *export.Final |
| 156 | + fallthrough |
| 157 | + |
| 158 | + default: |
| 159 | + p.ShowHidden = showAll |
| 160 | + } |
| 161 | + |
| 162 | + p.ShowDocs = showDocs |
| 163 | + p.ShowAttributes = showAll |
| 164 | + |
| 165 | + var n ast.Node |
| 166 | + if isDef { |
| 167 | + n, _ = p.Def(v.idx, pkgPath, v.v) |
| 168 | + } else { |
| 169 | + n, _ = p.Value(v.idx, pkgPath, v.v) |
| 170 | + } |
| 171 | + |
| 172 | + formatExpr(state, n) |
| 173 | +} |
| 174 | + |
| 175 | +func formatExpr(state fmt.State, n ast.Node) { |
| 176 | + opts := make([]format.Option, 0, 3) |
| 177 | + if state.Flag('-') { |
| 178 | + opts = append(opts, format.Simplify()) |
| 179 | + } |
| 180 | + // TODO: handle verbs to allow formatting based on type: |
| 181 | + if width, ok := state.Width(); ok { |
| 182 | + opts = append(opts, format.IndentPrefix(width)) |
| 183 | + } |
| 184 | + // TODO: consider this: should tabs or spaces be the default? |
| 185 | + if tabwidth, ok := state.Precision(); ok { |
| 186 | + // TODO: 0 means no newlines. |
| 187 | + opts = append(opts, |
| 188 | + format.UseSpaces(tabwidth), |
| 189 | + format.TabIndent(false)) |
| 190 | + } |
| 191 | + // TODO: consider this. |
| 192 | + // else if state.Flag(' ') { |
| 193 | + // opts = append(opts, |
| 194 | + // format.UseSpaces(4), |
| 195 | + // format.TabIndent(false)) |
| 196 | + // } |
| 197 | + |
| 198 | + b, _ := format.Node(n, opts...) |
| 199 | + b = bytes.Trim(b, "\n\r") |
| 200 | + _, _ = state.Write(b) |
| 201 | +} |
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