1	# src/args: bolt's command line, parsed by shake. `bolt [lint] [file..]`,
2	# `bolt check file..`, `bolt lsp`, `bolt --version`. A rest positional at the root (and on
3	# `lint` / `check`) takes every leftover word, so `bolt a.bend b.bend` lints
4	# those files. `help` is shake's usage page, and `--help` asks for the same
5	# page (`line`). IO.args gives the program as invoked first, then its
6	# arguments (bend 2.0.32); `argv` drops the program. A compiled binary passes
7	# its whole line through except its runtime options, which stand between
8	# `+RTS` and `-RTS` (bend 2.0.38): `--threads` and `--gpu` outside that
9	# bracket reach the program, and `--RTS` hands everything after it to the
10	# program. `--help` reaches the program (bend 2.0.29).
11	# `out` is every decision the line makes, as data: what to print, where, and
12	# the exit code, or the subcommand to run and its files. main only does it.
13	# Only shake's interface (main.bend) is read here; what `parse` answers for a
14	# given argv is shake's guarantee, not bolt's: shake v0.6.0, pinned by hash,
15	# proves it in its own gate, and the laws naming an argv take shake's answer as
16	# a premise and prove what bolt does with it. Of shake's assumptions bolt
17	# trusts one: the words a compiled bolt's argv holds are the runtime's (its
18	# options, between `+RTS` and `-RTS`, never reach it), which no law reaches.
19	import Base
20	import 0xa383b26a5a0ef35663b3615d7aedf9e3/main.bend as Shake
21	import ./version.bend as Ver
22	import ./build_rev.bend as Rev
23	import ./lazy/lazy.bend as Lazy
24	
25	# the line at the quantity the rest of bolt reads it at (IO.args gives each
26	# argument once)
27	def widen(ss: List<&1, String>) -> List<&2, String>:
28	  match ss:
29	    case Nil{}:
30	      Nil{}
31	    case Con{s, t}:
32	      s <> widen(t)
33	
34	# the arguments of IO.args's line: the program as invoked comes first, and is
35	# dropped
36	def args_of(ss: List<&1, String>) -> List<&2, String>:
37	  match ss:
38	    case Nil{}:
39	      Nil{}
40	    case Con{_prog, t}:
41	      widen(t)
42	
43	# bolt's command line: its arguments, without the program
44	def argv() -> IO(List<&2, String>):  # noqa: L001 IO: reads argv
45	  do IO<List<&2, String>>:
46	    ss : List<&1, String> <- IO.args()
47	    return args_of(ss)
48	
49	# whether a word names a subcommand
50	def is_cmd(+ww: String) -> Bool:
51	  Bool.or(String.eq(ww, "lint"), Bool.or(String.eq(ww, "check"), String.eq(ww, "lsp")))
52	
53	# whether `--help` stands among the words before the first `--` (after it,
54	# every word is a file); the search stops at either
55	def asks_help(ws: List<&2, String>) -> Bool:
56	  match ws:
57	    case Nil{}:
58	      False{}
59	    case Con{+ww, rest}:
60	      Lazy.and_then(Bool.not(String.eq(ww, "--")), _u => Lazy.or_else(String.eq(ww, "--help"), _v => asks_help(rest)))
61	
62	# the command path `--help` asks about: the first word other than `--help`,
63	# when it names a subcommand, else the root's
64	def help_path(ws: List<&2, String>) -> List<&2, String>:
65	  match ws:
66	    case Nil{}:
67	      Nil{}
68	    case Con{+ww, rest}:
69	      Lazy.either(List<&2, String>, String.eq(ww, "--help"), _u => help_path(rest),
70	        _u => Bool.pick(List<&2, String>, is_cmd(ww), [ww], []))
71	
72	# the line, given whether it asks for `--help`
73	def line.at(ask: Bool, +ws: List<&2, String>) -> List<&2, String>:
74	  match ask:
75	    case True{}:
76	      "help" <> help_path(ws)
77	    case False{}:
78	      ws
79	
80	# the line shake parses: one that asks for `--help` is `help` for its command
81	# path, the page `bolt help` prints; any other is itself
82	def line(+ws: List<&2, String>) -> List<&2, String>:
83	  line.at(asks_help(ws), ws)
84	
85	# the files rest, optional, last among positionals
86	def spec.files(+help: String) -> Shake.Arg:
87	  Shake.rest("files", help, False{}, None{}, [])
88	
89	# the release, with the short commit in parentheses when it is present
90	def version.at(+rel: String, +rev: String) -> String:
91	  Bool.pick(String, String.is_empty(rev), rel, rel ++ " (" ++ rev ++ ")")
92	
93	# the release, and the short commit when the build has one
94	def version() -> String:
95	  version.at(Ver.text(), Rev.text())
96	
97	# bolt's program spec
98	def spec() -> Shake.Cli:
99	  Shake.app("bolt", "A linter, checker and language server for Bend 2.", Some{version()},
100	    [Shake.flag("version", None{}, Some{"version"}, "Print the version"),
101	     spec.files("Files to lint")],
102	    [Shake.sub("lint", "Lint files", [spec.files("Files to lint")], []),
103	     Shake.sub("check", "Check files", [spec.files("Files to check")], []),
104	     Shake.sub("lsp", "Serve an editor over stdio", [], [])])
105	
106	# argv against bolt's spec
107	def parse(av: List<&2, String>) -> Result<&2, &2, Shake.ParseErr, Shake.Matched>:
108	  Shake.parse(spec(), av)
109	
110	# usage for a command path
111	def help_text(path: List<&2, String>) -> String:
112	  Shake.help(spec(), path)
113	
114	# a parse error as the text the binary prints
115	def err_text(ee: Shake.ParseErr) -> String:
116	  Shake.err_text(spec(), ee)
117	
118	# a subcommand
119	type Cmd is Data:
120	  CLint{}
121	  CCheck{}
122	  CLsp{}
123	
124	# a subcommand by its name; the empty name (no subcommand) is `lint`
125	def command(+name: String) -> Cmd:
126	  Bool.pick(Cmd, String.eq(name, "check"), CCheck{},
127	    Bool.pick(Cmd, String.eq(name, "lsp"), CLsp{}, CLint{}))
128	
129	# where a line that stops puts its text
130	type Stream is Data:
131	  Line{}
132	  Page{}
133	  Err{}
134	
135	# what a parsed line does: print a text and exit with a code, or run a
136	# subcommand over files (which then exits as that command decides)
137	type Out is Data:
138	  Stop{to: Stream, text: String, code: U32}
139	  Go{cmd: Cmd, paths: List<&2, String>}
140	
141	# the files the selected command bound: each command keeps its own
142	# bindings, so they are read from the Matched at the end of the selected
143	# path, which is the root's own when no subcommand was selected
144	def files.at(sel: Maybe<&2, Shake.Matched>, +mm: Shake.Matched) -> List<&2, String>:
145	  match sel:
146	    case Some{ss}:
147	      Shake.get_all(ss, "files")
148	    case None{}:
149	      Shake.get_all(mm, "files")
150	
151	# the files a successful parse bound, to the command it selected
152	def files(+mm: Shake.Matched) -> List<&2, String>:
153	  files.at(Shake.at(mm, Shake.path_of(mm)), mm)
154	
155	# a successful parse: the version, or the selected command and its files
156	def out.run(ask: Bool, +mm: Shake.Matched) -> Out:
157	  match ask:
158	    case True{}:
159	      Stop{Line{}, "bolt " ++ version(), 0}
160	    case False{}:
161	      Go{command(String.join(Shake.path_of(mm), "/")), files(mm)}
162	
163	# a failed parse, given whether it asked for usage: that usage page, or the
164	# error
165	def out.fail.at(asked: Maybe<&2, List<&2, String>>, +ee: Shake.ParseErr) -> Out:
166	  match asked:
167	    case Some{path}:
168	      Stop{Page{}, help_text(path), 0}
169	    case None{}:
170	      Stop{Err{}, err_text(ee), 1}
171	
172	# a failed parse: help text, or an error
173	def out.fail(+ee: Shake.ParseErr) -> Out:
174	  out.fail.at(Shake.help_path(ee), ee)
175	
176	# a successful parse, read once for the version flag
177	def out.done(+mm: Shake.Matched) -> Out:
178	  out.run(Shake.on(mm, "version"), mm)
179	
180	# what a parse result does
181	def out(rr: Result<&2, &2, Shake.ParseErr, Shake.Matched>) -> Out:
182	  match rr:
183	    case Fail{e}:
184	      out.fail(e)
185	    case Done{m}:
186	      out.done(m)