add logging

config.nims

@@ -23,7 +23,7 @@ task docs, "Deploy doc html + search index to public/ directory":
     gitFlags = fmt"--git.url:'https://github.com/daylinmorgan/{pkgName}' --git.commit:main"
   when defined(clean):
     rmDir deployDir
-  for module in ["cligen", "chooser"]:
+  for module in ["cligen", "chooser", "logging"]:
     selfExec fmt"doc --docRoot:{getCurrentDir()}/src/ --index:on --outdir:{deployDir} src/hwylterm/{module}"
   selfExec fmt"doc --project --index:on {gitFlags} --outdir:{deployDir} --project src/{pkgName}.nim"
   docFixup(deployDir,pkgName)

src/hwylterm/logging.nim

@@ -0,0 +1,118 @@
+import std/[logging, strutils]
+export logging
+
+import ./bbansi
+
+var
+  handlers {.threadvar.}: seq[Logger]
+
+#[
+Level* = enum ## \
+    lvlAll,     ## All levels active
+    lvlDebug,   ## Debug level and above are active
+    lvlInfo,    ## Info level and above are active
+    lvlNotice,  ## Notice level and above are active
+    lvlWarn,    ## Warn level and above are active
+    lvlError,   ## Error level and above are active
+    lvlFatal,   ## Fatal level and above are active
+    lvlNone     ## No levels active; nothing is logged
+]#
+
+type
+  FancyConsoleLogger* = ref object of Logger
+    ## A logger that writes log messages to the console.
+    ##
+    ## Create a new ``FancyConsoleLogger`` with the `newFancyConsoleLogger proc
+    ## <#newConsoleLogger>`_.
+    ##
+    useStderr*: bool ## If true, writes to stderr; otherwise, writes to stdout
+    flushThreshold*: Level ## Only messages that are at or above this
+                           ## threshold will be flushed immediately
+    fmtPrefix: string
+    fmtSep: string
+    fmtStrs: array[Level, string]
+
+
+const defaultFlushThreshold = lvlAll
+
+proc genFmtStr(
+  fmtPrefix, fmtSep, fmtSuffix, levelStyle: string,
+  level: Level
+): string =
+  var parts: seq[string]
+  if fmtPrefix != "": parts.add fmtPrefix
+  parts.add $LevelNames[level].bb(levelStyle)
+  return parts.join(fmtSep) & fmtSuffix
+
+
+proc newFancyConsoleLogger*(
+  levelThreshold = lvlAll,
+  fmtPrefix = "",
+  fmtSep = "|",
+  fmtSuffix = "| ",
+  useStderr = true,
+  flushThreshold = defaultFlushThreshold,
+  debugStyle = "faint",
+  infoStyle = "bold",
+  noticeStyle = "bold",
+  warnStyle = "bold yellow",
+  errorStyle = "bold red",
+  fatalStyle = "bold red"
+): FancyConsoleLogger =
+  ## Creates a new `FancyConsoleLogger<#ConsoleLogger>`_.
+  new result
+  ## log needs to be gcsafe so we pregenerate the log formats when making the handler
+  let fmtStrs: array[Level, string] = [
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, ""         , lvlAll),
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, debugStyle , lvlDebug),
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, infoStyle  , lvlInfo),
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, noticeStyle, lvlNotice),
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, warnStyle  , lvlWarn),
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, errorStyle , lvlError),
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, fatalStyle , lvlFatal),
+      genFmtStr(fmtPrefix, fmtSep, fmtSuffix, ""         , lvlNone)
+  ]
+  result.fmtPrefix = fmtPrefix
+  result.fmtSep = fmtSep
+  result.levelThreshold = levelThreshold
+  result.flushThreshold = flushThreshold
+  result.useStderr = useStderr
+  result.fmtStrs = fmtStrs
+
+
+method log*(logger: FancyConsoleLogger, level: Level, args: varargs[string, `$`]) {.gcsafe.} =
+  ## Logs to the console with the given `FancyConsoleLogger<#ConsoleLogger>`_ only.
+  ##
+  ## This method ignores the list of registered handlers.
+  ##
+  ## Whether the message is logged depends on both the ConsoleLogger's
+  ## ``levelThreshold`` field and the global log filter set using the
+  ## `setLogFilter proc<#setLogFilter,Level>`_.
+  ##
+  ## **Note:** Only error and fatal messages will cause the output buffer
+  ## to be flushed immediately by default. Set ``flushThreshold`` when creating
+  ## the logger to change this.
+
+  if level >= logger.levelThreshold:
+    let ln = substituteLog(logger.fmtStrs[level], level, args)
+    when defined(js): {.fatal: "handler does not support JS".}
+    try:
+      let handle =
+        if logger.useStderr: stderr
+        else: stdout
+      writeLine(handle, ln)
+      if level >= logger.flushThreshold: flushFile(handle)
+    except IOError:
+      discard
+
+proc addHandlers*(handler: Logger) =
+  handlers.add(handler)
+
+template errorQuit*(args: varargs[string, `$`]) =
+  error args
+  quit QuitFailure
+
+template fatalQuit*(args: varargs[string, `$`]) =
+  fatal args
+  quit QuitFailure
+