works w js too

compiler/jsgen.nim

@@ -434,7 +434,7 @@ const # magic checked op; magic unchecked op;
     mBoolToStr: ["nimBoolToStr", "nimBoolToStr"],
     mIntToStr: ["cstrToNimstr", "cstrToNimstr"],
     mInt64ToStr: ["cstrToNimstr", "cstrToNimstr"],
-    mFloatToStr: ["cstrToNimstr", "cstrToNimstr"],
+    mFloatToStr: ["cstrToNimstr", "cstrToNimstr"], # PRTEMP
     mCStrToStr: ["cstrToNimstr", "cstrToNimstr"],
     mStrToStr: ["", ""]]
 

lib/system.nim

@@ -2472,8 +2472,8 @@ when defined(js) or defined(nimscript):
   proc addInt*(result: var string; x: int64) =
     result.add $x
 
-  proc addFloat*(result: var string; x: float) =
-    result.add $x
+  # proc addFloat*(result: var string; x: float) =
+  #   result.add $x
 
 proc quit*(errormsg: string, errorcode = QuitFailure) {.noreturn.} =
   ## A shorthand for `echo(errormsg); quit(errorcode)`.

lib/system/dollars.nim

@@ -41,13 +41,9 @@ proc `$`*(x: int64): string {.magic: "Int64ToStr", noSideEffect.}
   ## The stringify operator for an integer argument. Returns `x`
   ## converted to a decimal string.
 
-proc `$`*(x: float): string {.magic: "FloatToStr", noSideEffect.}
-  ## The stringify operator for a float argument. Returns `x`
-  ## converted to a decimal string.
-
-proc `$`*(x: float32): string {.magic: "FloatToStr", noSideEffect.}
-  ## The stringify operator for a float32 argument. Returns `x`
-  ## converted to a decimal string.
+func `$`*(x: float | float32): string =
+  ## Outplace version of `addFloat`.
+  result.addFloat(x)
 
 proc `$`*(x: bool): string {.magic: "BoolToStr", noSideEffect.}
   ## The stringify operator for a boolean argument. Returns `x`

lib/system/formatfloat.nim

@@ -17,6 +17,12 @@ proc addCstringN(result: var string, buf: cstring; buflen: int) =
   let oldLen = result.len
   let newLen = oldLen + buflen
   result.setLen newLen
+  # when defined(js):
+  #   # debugEcho()
+  #   # for i in oldLen..<newLen:
+  #   for i in 0..<buflen:
+  #     result[oldLen + i] = buf[i]
+  # else:
   # copyMem(result[oldLen].addr, buf, buflen)
   c_memcpy(result[oldLen].addr, buf, buflen.csize_t)
 
@@ -99,6 +105,23 @@ proc addFloatSprintf*(result: var string; x: float) =
     let n = writeFloatToBufferSprintf(buffer, x)
     result.addCstringN(cstring(buffer[0].addr), n)
 
+proc nimFloatToString(a: float): cstring =
+  ## ensures the result doesn't print like an integer, i.e. return 2.0, not 2
+  # print `-0.0` properly
+  asm """
+    function nimOnlyDigitsOrMinus(n) {
+      return n.toString().match(/^-?\d+$/);
+    }
+    if (Number.isSafeInteger(`a`))
+      `result` = `a` === 0 && 1 / `a` < 0 ? "-0.0" : `a`+".0"
+    else {
+      `result` = `a`+""
+      if(nimOnlyDigitsOrMinus(`result`)){
+        `result` = `a`+".0"
+      }
+    }
+  """
+
 proc addFloat*(result: var string; x: float) {.inline.} =
   ## Converts float to its string representation and appends it to `result`.
   ##
@@ -107,10 +130,20 @@ proc addFloat*(result: var string; x: float) {.inline.} =
   ##     a = "123"
   ##     b = 45.67
   ##   a.addFloat(b) # a <- "12345.67"
-  when defined(nimFpRoundtrips):
-    addFloatRoundtrip(result, x)
-  else:
-    addFloatSprintf(result, x)
+  template impl =
+    when defined(nimFpRoundtrips):
+      addFloatRoundtrip(result, x)
+    else:
+      addFloatSprintf(result, x)
+  when defined(js):
+    when nimvm: impl()
+    else:
+      # result.add $nimFloatToString(x)
+      # result.add cstrToNimstr(nimFloatToString(x))
+      let tmp = nimFloatToString(x)
+      for i in 0..<tmp.len:
+        result.add tmp[i]
+  else: impl()
 
 proc nimFloatToStr(f: float): string {.compilerproc.} =
   result = newStringOfCap(8)

lib/system/repr_v2.nim

@@ -19,9 +19,9 @@ proc repr*(x: uint64): string {.noSideEffect.} =
   ## converted to a decimal string.
   $x #Calls `$` from system/strmantle.nim
 
-proc repr*(x: float): string {.magic: "FloatToStr", noSideEffect.}
-  ## repr for a float argument. Returns `x`
-  ## converted to a decimal string.
+proc repr*(x: float): string =
+  ## Same as $x
+  $x
 
 proc repr*(x: bool): string {.magic: "BoolToStr", noSideEffect.}
   ## repr for a boolean argument. Returns `x`