Squash level_parser into main: parse levels in CSV

commit b91ebeb77533cfab26dc28ae2e94bfb9f5d92aab
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 13:33:00 2023 -0800

    fix boss

    it works now except for a square being drawn in the shield. good enough

commit ab687f8f6d501a5b46043830482a6f84cc418aca
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 13:23:29 2023 -0800

    adjust spawning

    now it runs for a little tiny bit!

commit bef95df6a132f36ccd0f82a4b22c51fffad201bd
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 13:18:20 2023 -0800

    typo

commit 24435a3c1524d92f1d6c5ac0cf195592ba321d28
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 13:18:01 2023 -0800

    move guns before ships

commit 0c3a36f1fddcafa8b515eb98e6d9b1dde861375c
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 13:15:34 2023 -0800

    defer zap_gun creation until it exists

commit a39c419e5fadfc90866d16c3007898da601cbda2
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 13:13:51 2023 -0800

    fix mknew

commit 9ef762268f3a9405fd06bf46f6f981781bf3566f
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 13:04:13 2023 -0800

    many assorted syntax errors

commit e50f516b110d3d51d3a9adfa7f471b802ec9b801
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 12:00:34 2023 -0800

    allow strings when spawning guns

commit f9e28fa0e280aa0a03dc3c53218699de609fc221
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 11:59:20 2023 -0800

    fix missing paren

commit 38a054dec144c672ae58a4fe24ad325685953fcc
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 11:48:08 2023 -0800

    candidate conversion to csv for level format

commit fd391ff3bc70276a2852f738bb9492eb5968d900
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 11:40:11 2023 -0800

    use _ENV to get rid of level_events and spawns

commit fbd9f97429533684a7b0357855d74c7b23eb6bb5
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Wed Dec 20 11:33:59 2023 -0800

    maybe fix the level parser

commit 2a61e8b5d6aba26cc6ab44c602bab867ac2bb9ad
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Sun Oct 15 21:09:12 2023 -0700

    partial conversion to CSV-based levels, does not run yet

commit 4ccbe1dc3541d7317b9871c420c2dfadd36da73c
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Fri Oct 13 01:02:43 2023 -0700

    okay honestly this all can and should just be CSVs

commit b536d2c9875b34300dd1e7c9f11345fd89f603df
Author: Kistaro Windrider <kistaro@gmail.com>
Date:   Sun Oct 8 00:41:24 2023 -0700

    base for representing a level as a string

the_parser.p8

@@ -0,0 +1,61 @@
+pico-8 cartridge // http://www.pico-8.com
+version 41
+__lua__
+-- the parser
+
+parser = {}
+mknew(parser)
+
+-- calls parse_into with a nop
+-- emit function.
+function parser:parse(str)
+ self:parse_into(str, function() end)
+end
+
+-- read a file of commands and
+-- execute them, emitting the
+-- results from each call into
+-- `emit` as a table per row.
+--
+-- a "command" is a method on
+-- self. a row alternates
+-- commands with args. when
+-- calling a command, it also
+-- gets a table of previous
+-- results as the first arg.
+-- args are split on ','.
+function parser:parse_into(str, emit)
+ for row in all(split(str, "\n")) do
+  local prev = {}
+  local sectors = split(row, ":")
+  for i=1,#sectors,2 do
+   local x = self[sectors[i]](self, prev, usplit(sectors[i+1]))
+   if (x) add(prev, x)
+  end
+  emit(prev)
+ end
+end
+
+-- saves prev[sel] as self.name.
+-- if sel is unspecified, saves
+-- all of prev (as a table).
+function parser:saveas(prev, name, sel)
+ self[name] = sel and prev[sel] or prev
+end
+
+-- returns its args, ignoring
+-- prev. Used to stuff things
+-- into prev. args are packed
+-- if there's multiple.
+function parser:val(_, ...)
+ local ret := pack(...)
+ if (#ret == 1) return ret[1]
+ return ret
+end
+
+function parser:bind(_, fn, ...)
+ local f = self[fn]
+ return function()
+  f(...)
+ end
+end