NIR: Nim intermediate representation (#22777)

Theoretical Benefits / Plans: 

- Typed assembler-like language.
- Allows for a CPS transformation.
- Can replace the existing C backend by a new C backend.
- Can replace the VM.
- Can do more effective "not nil" checking and static array bounds
checking.
- Can be used instead of the DFA.
- Easily translatable to LLVM.
- Reasonably easy to produce native code from.
- Tiny memory consumption. No pointers, no cry.

**In very early stages of development.**

Todo:
- [x] Map Nim types to IR types.
- [ ] Map Nim AST to IR instructions:
  - [x] Map bitsets to bitops.
  - [ ] Implement string cases.
  - [ ] Implement range and index checks.
  - [x] Implement `default(T)` builtin.
  - [x] Implement multi string concat.
- [ ] Write some analysis passes.
- [ ] Write a backend.
- [x] Integrate into the compilation pipeline.

1 files changed, 16 insertions, 15 deletions

diff --git a/lib/std/formatfloat.nim b/lib/std/formatfloat.nim
index 48973aa55..872549c3b 100644
--- a/lib/std/formatfloat.nim
+++ b/lib/std/formatfloat.nim
@@ -100,22 +100,23 @@ proc addFloatSprintf*(result: var string; x: float) =
     let n = writeFloatToBufferSprintf(buffer, x)
     result.addCstringN(cast[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+$/);
-    }
-    if (Number.isSafeInteger(`a`))
-      `result` = `a` === 0 && 1 / `a` < 0 ? "-0.0" : `a`+".0"
-    else {
-      `result` = `a`+""
-      if(nimOnlyDigitsOrMinus(`result`)){
-        `result` = `a`+".0"
+when defined(js):
+  proc nimFloatToString(a: float): cstring =
+    ## ensures the result doesn't print like an integer, i.e. return 2.0, not 2
+    # print `-0.0` properly
+    asm """
+      function nimOnlyDigitsOrMinus(n) {
+        return n.toString().match(/^-?\d+$/);
       }
-    }
-  """
+      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 | float32) {.inline.} =
   ## Converts float to its string representation and appends it to `result`.