HCoop / hcoop / debian / mlton.git / blame
| Commit | Line | Data |
|---|---|---|
| 7f918cf1 CE |
1 | ImplementSuffix |
| 2 | =============== | |
| 3 | ||
| 4 | <:ImplementSuffix:> is a pass for the <:SXML:> | |
| 5 | <:IntermediateLanguage:>, invoked from <:SXMLSimplify:>. | |
| 6 | ||
| 7 | == Description == | |
| 8 | ||
| 9 | This pass implements the `TopLevel_setSuffix` primitive, which | |
| 10 | installs a function to exit the program. | |
| 11 | ||
| 12 | == Implementation == | |
| 13 | ||
| 14 | * <!ViewGitFile(mlton,master,mlton/xml/implement-suffix.fun)> | |
| 15 | ||
| 16 | == Details and Notes == | |
| 17 | ||
| 18 | <:ImplementSuffix:> works by introducing a new `ref` cell to contain | |
| 19 | the function of type `unit -> unit` that should be called on program | |
| 20 | exit. | |
| 21 | ||
| 22 | * The following code (appropriately alpha-converted) is appended to the beginning of the <:SXML:> program: | |
| 23 | + | |
| 24 | [source,sml] | |
| 25 | ---- | |
| 26 | val z_0 = | |
| 27 | fn a_0 => | |
| 28 | let | |
| 29 | val x_0 = | |
| 30 | "toplevel suffix not installed" | |
| 31 | val x_1 = | |
| 32 | MLton_bug (x_0) | |
| 33 | in | |
| 34 | x_1 | |
| 35 | end | |
| 36 | val topLevelSuffixCell = | |
| 37 | Ref_ref (z_0) | |
| 38 | ---- | |
| 39 | ||
| 40 | * Any occurrence of | |
| 41 | + | |
| 42 | [source,sml] | |
| 43 | ---- | |
| 44 | val x_0 = | |
| 45 | TopLevel_setSuffix (f_0) | |
| 46 | ---- | |
| 47 | + | |
| 48 | is rewritten to | |
| 49 | + | |
| 50 | [source,sml] | |
| 51 | ---- | |
| 52 | val x_0 = | |
| 53 | Ref_assign (topLevelSuffixCell, f_0) | |
| 54 | ---- | |
| 55 | ||
| 56 | * The following code (appropriately alpha-converted) is appended to the end of the <:SXML:> program: | |
| 57 | + | |
| 58 | [source,sml] | |
| 59 | ---- | |
| 60 | val f_0 = | |
| 61 | Ref_deref (topLevelSuffixCell) | |
| 62 | val z_0 = | |
| 63 | () | |
| 64 | val x_0 = | |
| 65 | f_0 z_0 | |
| 66 | ---- |