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# ez/start: what `ez check`, `ez build` and `ez run` start, decided from the# ledger they read and the words they were given. Each starts one bend on# the entry the ledger names, or refuses and starts nothing when there is no# ez.toml or it does not parse, as cargo refuses a directory with no# Cargo.toml. The interpreter (`ez/cmd.bend`) reads ez.toml, puts the# project's BEND_LIB in front of the line (`Env.line`), runs it and exits;# that it does so faithfully is EZ-TRUST-2.import Baseimport ../ledger/manifest.bend as Mimport ../share/args.bend as Args# which of the three commands is asking, with what it was told: where a# build goes, and every word of the line for a runtype Ask is Data:  Check{}  Build{out: String}  Run{as: List<&2, String>}# what a command does: refuse with a reason, having started nothing, or start# bend with this linetype Start is Data:  Refused{why: String}  Starts{line: List<&2, String>}# what each command is for, in the words a refusal says it withdef does(ask: Ask) -> String:  match ask:    case Check{}:      "ez check checks a project's entry"    case Build{_out}:      "ez build builds a project's entry"    case Run{_as}:      "ez run runs a project's entry"# why a directory with no ez.toml is refuseddef none(ask: Ask) -> String:  "ez: no ez.toml here; " ++ does(ask) ++ ", and ez init makes one"# the entry file a ledger names, or "main.bend" when it names nonedef entry.or(+file: String) -> String:  Bool.pick(String, String.is_empty(file), "main.bend", file)# the entry file of a ledger that parseddef entry(ledger: M.Manifest) -> String:  M.Manifest{_n, e, _b, _h, _pa, _pv, _ds, _ts} = ledger  entry.or(e)# the name a ledger that parsed gives the packagedef named(ledger: M.Manifest) -> String:  M.Manifest{n, _e, _b, _h, _pa, _pv, _ds, _ts} = ledger  n# where a build lands when nothing said: `bin/<package name>.out`. The name# and not the entry file, because the entry is where a program starts and the# name is what it is called: a package named `bolt` with its entry at# `bolt/main.bend` builds `bin/bolt.out` and not `bin/main.out`.def build.named(+name: String) -> String:  "bin/" ++ name ++ ".out"# where a build lands: what was asked for, or the defaultdef build.out(+at: String, +name: String) -> String:  Bool.pick(String, String.is_empty(at), build.named(name), at)# the line each command starts bend with, over a ledger that parsed: the# entry checked into `.ez/check.js` and never run, built to a native binary,# or run with every word after `run` (EZ-TOOL-9)def line(ask: Ask, +ledger: M.Manifest) -> List<&2, String>:  match ask:    case Check{}:      ["bend", entry(ledger), "-o", ".ez/check.js"]    case Build{+out}:      ["bend", entry(ledger), "-o", build.out(out, named(ledger))]    case Run{as}:      Args.run.line(entry(ledger), as)# what a command does with the ledger it readdef read(+ask: Ask, ledger: M.Read) -> Start:  match ledger:    case M.Bad{why}:      Refused{"ez: " ++ M.show(M.Bad{why})}    case M.Good{+m}:      Starts{line(ask, m)}# what a command does with ez.toml's text, None when there is nonedef start(+ask: Ask, text: Maybe<&2, String>) -> Start:  match text:    case None{}:      Refused{none(ask)}    case Some{t}:      read(ask, M.parse(t))# the status `ez run` exits with, given the status of the program it started# (EZ-OUT-1): 1 for a refusal, which started none, and the program's own# status otherwise, as `cargo run` exits. `ez check` and `ez build` end on# what bend printed instead (`ez/ends.bend`).def code(start: Start, program: U32) -> U32:  match start:    case Refused{_why}:      1    case Starts{_line}:      program# why a command refused, or "" when it started benddef why(start: Start) -> String:  match start:    case Refused{w}:      w    case Starts{_line}:      ""