Add a new bqn.bqn that uses the VM

1 files changed, 60 insertions, 0 deletions

diff --git a/bqn.bqn b/bqn.bqn
new file mode 100755
index 00000000..086907e2
--- /dev/null
+++ b/bqn.bqn
@@ -0,0 +1,60 @@
+#! /usr/bin/env bqn
+
+# A BQN interpreter implemented in BQN
+# ./bqn.bqn ( files | -e source )
+
+# Unlike a compiler, a self-hosted interpreter is kind of silly. This
+# script is mostly just evidence that the BQN components found in this
+# repository do add up to a full implementation. The same idea more
+# usefully applied in test/unit.bqn, which can build an interpreter
+# using some or all of them in order to test it.
+
+# BQN's compiler is truly self-hosting, but targets a BQN-specific
+# object code rather than machine code (as does Java). The virtual
+# machine interprets this object code. Finally, the compiler takes
+# primitive values as input in order to include them in the object code.
+# As all primitives are available in BQN we could just use these, but
+# for more self-hostingness the BQN-based runtime is used instead, so
+# that the interpreter relies on a smaller set of core functions.
+
+#⌜
+# Assemble the components
+gl ← •Import "src/glyphs.bqn"
+compile ← gl •Import "src/c.bqn"  # Compiler: source → object code
+vm      ←    •Import "vm.bqn"     # VM: interprets object code
+runtime ←    •Import "rt.bqn"     # Runtime: primitives available to VM
+
+# Define system values later, to include BQN
+BQN ← ⟨runtime, {System 𝕩}⟩ ⊸ (VM Compile)
+
+#⌜
+# System values
+IsPrim ← ∊⟜runtime⌾<
+Glyph ← runtime⊸⊐⌾<⊑(∾gl)˙
+Decompose ← IsPrim◶⟨•Decompose,0⊸≍⟩
+
+# Formatter
+tn ← "*"⊸(∾∾⊣)¨"array"‿"function"‿"1-modifier"‿"2-modifier"‿"namespace"
+Fmt‿Repr ← (•Import "src/f.bqn"){𝔽} ⟨
+  •Type
+  Decompose
+  IsPrim◶⟨tn⊑˜•Type-2˙, Glyph⟩ # Format operation/namespace
+  •Repr                        # Format number
+⟩
+
+# Lookup table
+FindSys ← {
+  i ← 𝕨⊐𝕩
+  { ! ∾⟨"Unknown system value",(1≠≠𝕩)/"s",":"⟩∾" •"⊸∾¨𝕩 }∘/⟜𝕩⍟(∨´) i=≠𝕨
+  i
+}
+system ← {𝕨⊸FindSys⊏𝕩˙}´⟨
+  "bqn"‿"type"‿"glyph"‿"decompose"‿"repr"‿"fmt"‿"out"‿"show"
+   BQN ‿•Type ‿ Glyph ‿ Decompose ‿ Repr ‿ Fmt ‿•Out ‿(•Out Fmt)
+⟩
+
+#⌜
+# Evaluate:
+(BQN¨ ("-e"≡⊑)◶⟨•file.Chars¨, 1⊸↓⟩)⍟(0<≠) •args
+
+BQN  # Return the evaluator so it can be •Include d from BQN