Corrections to preserves-schema host-type generation; extract host-type schema

preserves-schema.md

@@ -4,7 +4,7 @@ title: "Preserves Schema"
 ---
 
 Tony Garnock-Jones <tonyg@leastfixedpoint.com>  
-October 2023. Version 0.3.4.
+December 2023. Version 0.3.5.
 
   [abnf]: https://tools.ietf.org/html/rfc7405
   [identifierlike]: #sufficiently-identifierlike-values
@@ -470,7 +470,7 @@ The host-language types corresponding to a metaschema instance can
 themselves be described according to a grammar.
 
 The definitions in this section should be understood as being part of a
-module named `host`, in a bundle alongside a module named `schema`
+module named [`host`](schema/host.prs), in a bundle alongside a module named `schema`
 corresponding to the metaschema in the appendix below.
 
 #### Abstract host language types
@@ -555,7 +555,8 @@ patterns, **product**{:.pseudocode} yields `unit` type itself.
 > **gather** `<tuple [`*f`1` .. f`n`*`]>` = **gather** *f`1`* ⧺ ⋯ ⧺ **gather** *f`n`*
 > **gather** `<tuplePrefix [`*f`1` ... f`n`*`]` *f`repeated`*`>` = **gather** *f`1`* ⧺ ⋯ ⧺ **gather** *f`n`* ⧺ **gather** *f`repeated`*
 > **gather** `<dict {`*v`1`*`:`*f`1` ... v`n`*`:`*f`n`*`}>` = **gather** *f`1`′* ⧺ ⋯ ⧺ **gather** *f`n`′*,
->     where (*f`1`′ ⋯ f`n`′*) are (*f`1` ⋯ f`n`*) sorted according to [Preserves term order](./preserves.html#total-order).
+>     where (*f`1`′ ⋯ f`n`′*) are the *f`i`* sorted by [Preserves term order](./preserves.html#total-order) of the corresponding *v`i`*.
+> **gather** *s* = `[]`, when *s* ∈ `schema.SimplePattern`.
 
 ## Appendix: Metaschema
 

schema/Makefile

@@ -1,8 +1,8 @@
-all: schema.bin
+all: schema.bin host.bin
 
-schema.bin: schema.prs
-	../implementations/javascript/packages/schema-cli/bin/preserves-schemac.js --no-bundle .:schema.prs > $@.tmp || (rm -f $@.tmp; false)
+%.bin: %.prs
+	../implementations/javascript/packages/schema-cli/bin/preserves-schemac.js --no-bundle .:$< > $@.tmp || (rm -f $@.tmp; false)
 	mv $@.tmp $@
 
 clean:
-	rm -f schema.bin
+	rm -f schema.bin host.bin

schema/host.bin

@@ -0,0 +1,4 @@
+´³schema·³version°

³definitions·³Field´³orµµ±unit´³lit³unit„„µ±any´³lit³any„„µ±embedded´³lit³embedded„„µ±array´³rec´³lit³array„´³tupleµ´³named³element´³refµ„³Field„„„„„„µ±set´³rec´³lit³set„´³tupleµ´³named³element´³refµ„³Field„„„„„„µ±map´³rec´³lit³map„´³tupleµ´³named³key´³refµ„³Field„„´³named³value´³refµ„³Field„„„„„„µ±ref´³rec´³lit³ref„´³tupleµ´³named³name´³refµ³schema„³Ref„„„„„„µ±AtomKind´³refµ³schema„³AtomKind„„„„³Record´³rec´³lit³rec„´³tupleµ´³named³fields´³seqof´³refµ„³
+NamedField„„„„„„³Simple´³orµµ±Field´³refµ„³Field„„µ±Record´³refµ„³Record„„„„³Variant´³tupleµ´³named³label´³atom³Symbol„„´³named³type´³refµ„³Simple„„„„³
+Definition´³orµµ±union´³rec´³lit³union„´³tupleµ´³named³variants´³seqof´³refµ„³Variant„„„„„„„µ±Simple´³refµ„³Simple„„„„³
+NamedField´³tupleµ´³named³name´³atom³Symbol„„´³named³type´³refµ„³Field„„„„„³embeddedType€„„

schema/host.prs

@@ -0,0 +1,19 @@
+version 1 .
+
+Definition = <union @variants [Variant ...]> / Simple .
+Variant = [@label symbol @type Simple] .
+
+Simple = Field / Record .
+Record = <rec @fields [NamedField ...]> .
+NamedField = [@name symbol @type Field] .
+
+Field =
+/ =unit
+/ =any
+/ =embedded
+/ <array @element Field>
+/ <set @element Field>
+/ <map @key Field @value Field>
+/ <ref @name schema.Ref>
+/ schema.AtomKind
+.