| 1 | # args.ysh
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| 2 | #
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| 3 | # Usage:
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| 4 | # source --builtin args.sh
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| 5 |
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| 6 | const __provide__ = :| parser parseArgs |
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| 7 |
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| 8 | #
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| 9 | #
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| 10 | # parser (&spec) {
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| 11 | # flag -v --verbose (help="Verbosely") # default is Bool, false
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| 12 | #
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| 13 | # flag -P --max-procs (Int, default=-1, doc='''
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| 14 | # Run at most P processes at a time
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| 15 | # ''')
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| 16 | #
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| 17 | # flag -i --invert (Bool, default=true, doc='''
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| 18 | # Long multiline
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| 19 | # Description
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| 20 | # ''')
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| 21 | #
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| 22 | # arg src (help='Source')
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| 23 | # arg dest (help='Dest')
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| 24 | # arg times (help='Foo')
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| 25 | #
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| 26 | # rest files
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| 27 | # }
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| 28 | #
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| 29 | # var args = parseArgs(spec, ARGV)
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| 30 | #
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| 31 | # echo "Verbose $[args.verbose]"
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| 32 |
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| 33 | # TODO: See list
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| 34 | # - flag builtin:
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| 35 | # - handle only long flag or only short flag
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| 36 | # - flag aliases
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| 37 | # - assert that default value has the declared type
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| 38 |
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| 39 | proc parser (; place ; ; block_def) {
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| 40 | ## Create an args spec which can be passed to parseArgs.
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| 41 | ##
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| 42 | ## Example:
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| 43 | ##
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| 44 | ## # NOTE: &spec will create a variable named spec
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| 45 | ## parser (&spec) {
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| 46 | ## flag -v --verbose (Bool)
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| 47 | ## }
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| 48 | ##
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| 49 | ## var args = parseArgs(spec, ARGV)
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| 50 |
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| 51 | var p = {flags: [], args: []}
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| 52 | ctx push (p) {
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| 53 | call io->eval(block_def, vars={flag, arg, rest})
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| 54 | }
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| 55 |
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| 56 | # Validate that p.rest = [name] or null and reduce p.rest into name or null.
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| 57 | if ('rest' in p) {
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| 58 | if (len(p.rest) > 1) {
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| 59 | error '`rest` was called more than once' (code=3)
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| 60 | } else {
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| 61 | setvar p.rest = p.rest[0]
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| 62 | }
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| 63 | } else {
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| 64 | setvar p.rest = null
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| 65 | }
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| 66 |
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| 67 | var names = {}
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| 68 | for items in ([p.flags, p.args]) {
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| 69 | for x in (items) {
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| 70 | if (x.name in names) {
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| 71 | error "Duplicate flag/arg name $[x.name] in spec" (code=3)
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| 72 | }
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| 73 |
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| 74 | setvar names[x.name] = null
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| 75 | }
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| 76 | }
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| 77 |
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| 78 | # TODO: what about `flag --name` and then `arg name`?
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| 79 |
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| 80 | call place->setValue(p)
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| 81 | }
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| 82 |
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| 83 | const kValidTypes = [Bool, Float, List[Float], Int, List[Int], Str, List[Str]]
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| 84 | const kValidTypeNames = []
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| 85 | for vt in (kValidTypes) {
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| 86 | var name = vt.name if ('name' in propView(vt)) else vt.unique_id
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| 87 | call kValidTypeNames->append(name)
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| 88 | }
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| 89 |
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| 90 | func isValidType (type) {
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| 91 | for valid in (kValidTypes) {
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| 92 | if (type is valid) {
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| 93 | return (true)
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| 94 | }
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| 95 | }
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| 96 | return (false)
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| 97 | }
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| 98 |
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| 99 | proc flag (short, long ; type=Bool ; default=null, help=null) {
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| 100 | ## Declare a flag within an `arg-parse`.
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| 101 | ##
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| 102 | ## Examples:
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| 103 | ##
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| 104 | ## arg-parse (&spec) {
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| 105 | ## flag -v --verbose
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| 106 | ## flag -n --count (Int, default=1)
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| 107 | ## flag -p --percent (Float, default=0.0)
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| 108 | ## flag -f --file (Str, help="File to process")
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| 109 | ## flag -e --exclude (List[Str], help="File to exclude")
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| 110 | ## }
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| 111 |
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| 112 | if (type !== null and not isValidType(type)) {
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| 113 | var type_names = ([null] ++ kValidTypeNames) => join(', ')
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| 114 | error "Expected flag type to be one of: $type_names" (code=2)
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| 115 | }
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| 116 |
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| 117 | # Bool has a default of false, not null
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| 118 | if (type is Bool and default === null) {
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| 119 | setvar default = false
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| 120 | }
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| 121 |
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| 122 | var name = long => trimStart('--')
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| 123 |
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| 124 | ctx emit flags ({short, long, name, type, default, help})
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| 125 | }
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| 126 |
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| 127 | proc arg (name ; ; help=null) {
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| 128 | ## Declare a positional argument within an `arg-parse`.
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| 129 | ##
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| 130 | ## Examples:
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| 131 | ##
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| 132 | ## arg-parse (&spec) {
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| 133 | ## arg name
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| 134 | ## arg config (help="config file path")
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| 135 | ## }
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| 136 |
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| 137 | ctx emit args ({name, help})
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| 138 | }
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| 139 |
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| 140 | proc rest (name) {
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| 141 | ## Take the remaining positional arguments within an `arg-parse`.
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| 142 | ##
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| 143 | ## Examples:
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| 144 | ##
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| 145 | ## arg-parse (&grepSpec) {
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| 146 | ## arg query
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| 147 | ## rest files
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| 148 | ## }
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| 149 |
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| 150 | # We emit instead of set to detect multiple invocations of "rest"
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| 151 | ctx emit rest (name)
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| 152 | }
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| 153 |
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| 154 | func parseArgs(spec, argv) {
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| 155 | ## Given a spec created by `parser`. Parse an array of strings `argv` per
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| 156 | ## that spec.
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| 157 | ##
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| 158 | ## See `parser` for examples of use.
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| 159 |
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| 160 | var i = 0
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| 161 | var positionalPos = 0
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| 162 | var argc = len(argv)
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| 163 | var args = {}
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| 164 | var rest = []
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| 165 |
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| 166 | var value
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| 167 | var found
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| 168 | var escape_remaining = false
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| 169 | while (i < argc) {
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| 170 | var arg = argv[i]
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| 171 |
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| 172 | if (escape_remaining) {
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| 173 | call rest->append(arg)
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| 174 | } elif (arg === '--') {
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| 175 | if (not spec.rest) {
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| 176 | error "Unexpected '--' argument - extraneous positional arguments are prohibited" (code=2)
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| 177 | }
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| 178 |
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| 179 | setvar escape_remaining = true
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| 180 | } elif (arg.startsWith('-')) {
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| 181 | setvar found = false
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| 182 |
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| 183 | for flag in (spec.flags) {
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| 184 | if ( (flag.short and flag.short === arg) or
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| 185 | (flag.long and flag.long === arg) ) {
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| 186 | if (flag.type === null or flag.type is Bool) {
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| 187 | setvar value = true
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| 188 | } elif (flag.type is Int) {
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| 189 | setvar i += 1
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| 190 | if (i >= len(argv)) {
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| 191 | error "Expected Int after '$arg'" (code=2)
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| 192 | }
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| 193 |
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| 194 | try { setvar value = int(argv[i]) }
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| 195 | if failed {
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| 196 | error "Expected Int after '$arg', got '$[argv[i]]'" (code=2)
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| 197 | }
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| 198 | } elif (flag.type is List[Int]) {
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| 199 | setvar i += 1
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| 200 | if (i >= len(argv)) {
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| 201 | error "Expected Int after '$arg'" (code=2)
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| 202 | }
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| 203 |
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| 204 | setvar value = get(args, flag.name, [])
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| 205 | try { call value->append(int(argv[i])) }
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| 206 | if failed {
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| 207 | error "Expected Int after '$arg', got '$[argv[i]]'" (code=2)
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| 208 | }
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| 209 | } elif (flag.type is Float) {
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| 210 | setvar i += 1
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| 211 | if (i >= len(argv)) {
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| 212 | error "Expected Float after '$arg'" (code=2)
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| 213 | }
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| 214 |
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| 215 | try { setvar value = float(argv[i]) }
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| 216 | if failed {
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| 217 | error "Expected Float after '$arg', got '$[argv[i]]'" (code=2)
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| 218 | }
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| 219 | } elif (flag.type is List[Float]) {
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| 220 | setvar i += 1
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| 221 | if (i >= len(argv)) {
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| 222 | error "Expected Float after '$arg'" (code=2)
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| 223 | }
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| 224 |
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| 225 | setvar value = get(args, flag.name, [])
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| 226 | try { call value->append(float(argv[i])) }
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| 227 | if failed {
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| 228 | error "Expected Float after '$arg', got '$[argv[i]]'" (code=2)
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| 229 | }
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| 230 | } elif (flag.type is Str) {
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| 231 | setvar i += 1
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| 232 | if (i >= len(argv)) {
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| 233 | error "Expected Str after '$arg'" (code=2)
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| 234 | }
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| 235 |
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| 236 | setvar value = argv[i]
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| 237 | } elif (flag.type is List[Str]) {
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| 238 | setvar i += 1
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| 239 | if (i >= len(argv)) {
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| 240 | error "Expected Str after '$arg'" (code=2)
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| 241 | }
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| 242 |
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| 243 | setvar value = get(args, flag.name, [])
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| 244 | call value->append(argv[i])
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| 245 | }
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| 246 |
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| 247 | setvar args[flag.name] = value
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| 248 | setvar found = true
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| 249 | break
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| 250 | }
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| 251 | }
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| 252 |
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| 253 | if (not found) {
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| 254 | error "Unknown flag '$arg'" (code=2)
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| 255 | }
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| 256 | } elif (positionalPos >= len(spec.args)) {
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| 257 | if (not spec.rest) {
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| 258 | error "Too many arguments, unexpected '$arg'" (code=2)
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| 259 | }
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| 260 |
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| 261 | call rest->append(arg)
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| 262 | } else {
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| 263 | var pos = spec.args[positionalPos]
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| 264 | setvar positionalPos += 1
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| 265 | setvar value = arg
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| 266 | setvar args[pos.name] = value
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| 267 | }
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| 268 |
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| 269 | setvar i += 1
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| 270 | }
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| 271 |
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| 272 | if (spec.rest) {
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| 273 | setvar args[spec.rest] = rest
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| 274 | }
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| 275 |
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| 276 | # Set defaults for flags
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| 277 | for flag in (spec.flags) {
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| 278 | if (flag.name not in args) {
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| 279 | setvar args[flag.name] = flag.default
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| 280 | }
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| 281 | }
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| 282 |
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| 283 | # Raise error on missing args
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| 284 | for arg in (spec.args) {
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| 285 | if (arg.name not in args) {
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| 286 | error "Usage Error: Missing required argument $[arg.name]" (code=2)
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| 287 | }
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| 288 | }
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| 289 |
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| 290 | return (args)
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| 291 | }
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