Add --cacheDir option

src/config.nim

@@ -79,9 +79,11 @@ Options
 --listWarns               Show a list of all warnings
 -b, --backend             Select the compilation backend. Currently only supports 'bytecode' (the default)
 -c, --compile             Compile the code, but do not run the main module
--o, --output              Rename the output executable to this (a "pn" extension is added for bytecode files,
+-o, --output              Rename the output executable to this (a "bc" extension is added for bytecode files,
                           if not already present)
 -s, --string              Run the given string as if it were a file (the filename is set to '<string>')
+--cacheDir                Specify a directory where the peon compiler will dump code generation results
+                          to speed up subsequent builds. Defaults to ".buildcache"
 
 The following options are specific to the 'bytecode' backend:
   -n, --noDump              Do not dump bytecode files to the source directory. Note that

src/peon.nim

@@ -68,7 +68,7 @@ proc `$`(self: TypedNode): string =
 
 proc runFile(filename: string, fromString: bool = false, dump: bool = true, generate: bool = true, breakpoints: seq[uint64] = @[],
              disabledWarnings: seq[WarningKind] = @[], mismatches: bool = false, run: bool = true, 
-             backend: PeonBackend = PeonBackend.Bytecode, output: string) =
+             backend: PeonBackend = PeonBackend.Bytecode, output: string, cacheDir: string) =
     var
         tokens: seq[Token]
         tree: ParseTree
@@ -141,7 +141,9 @@ proc runFile(filename: string, fromString: bool = false, dump: bool = true, gene
                 if dump and not fromString:
                     if not output.endsWith(".pbc"):
                         output.add(".pbc")
-                    serializer.dumpFile(chunk, filename, output)
+                    if not dirExists(cacheDir):
+                        createDir(cacheDir)
+                    serializer.dumpFile(chunk, joinPath(cacheDir, filename), output)
                 if debugCompiler:
                     styledEcho fgCyan, "Disassembler output below"
                     debugger.disassembleChunk(chunk, filename)
@@ -275,6 +277,7 @@ when isMainModule:
         dump = true
         warnings: seq[WarningKind] = @[]
         showMismatches = false
+        cachePath: string = ".buildcache"
         #mode: CompileMode = CompileMode.Debug
         run = true
         generateCode = true
@@ -355,6 +358,8 @@ when isMainModule:
                         debugLexer = true
                     of "debugParser":
                         debugParser = true
+                    of "cachePath":
+                        cachePath = value
                     of "breakpoints":
                         when debugVM:
                             for point in value.strip(chars={' '}).split(","):
@@ -405,4 +410,4 @@ when isMainModule:
         echo "Sorry, the REPL is broken :("
         # repl(warnings, showMismatches, backend, dump)
     else:
-        runFile(file, fromString, dump, generateCode, breakpoints, warnings, showMismatches, run, backend, output)
+        runFile(file, fromString, dump, generateCode, breakpoints, warnings, showMismatches, run, backend, output, cachePath)