diff options
| -rw-r--r-- | README.md | 4 | ||||
| -rw-r--r-- | src/lvm.js | 55 | ||||
| -rw-r--r-- | tests/lvm.js | 22 |
3 files changed, 78 insertions, 3 deletions
@@ -4,9 +4,7 @@ ## So far - [x] Parse bytecode -- [ ] Opcodes - - [x] ... - - [ ] `OP_CONCAT` +- [x] Opcodes - [ ] Basic types representation: - [x] nil - [x] boolean @@ -11,6 +11,7 @@ const LUA_MULTRET = lua.LUA_MULTRET; const lobject = require('./lobject.js'); const TValue = lobject.TValue; const Table = lobject.Table; +const TString = lobject.TString; const LClosure = lobject.LClosure; const lfunc = require('./lfunc.js'); const UpVal = lfunc.UpVal; @@ -381,6 +382,16 @@ const luaV_execute = function(L) { break; } case "OP_CONCAT": { + let b = i.B; + let c = i.C; + let rb; + L.top = base + c + 1; /* mark the end of concat operands */ + luaV_concat(L, c - b + 1); + base = ci.u.l.base; + ra = RA(L, base, i); /* 'luaV_concat' may invoke TMs and move the stack */ + rb = base + b; + L.stack[ra] = L.stack[rb]; + L.top = ci.top; /* restore top */ break; } case "OP_JMP": { @@ -873,12 +884,56 @@ const luaV_objlen = function(L, ra, rb) { ltm.luaT_callTM(L, tm, rb, rb, ra, 1); }; +const tostring = function(L, i) { + let o = L.stack[i]; + let str = `${o.value}`; + + if (o.ttisstring() || (o.ttisnumber() && !isNaN(parseFloat(`${str}`)))) { + L.stack[i] = new TString(str); + return true; + } + + return false; +}; + /* ** Main operation for concatenation: concat 'total' values in the stack, ** from 'L->top - total' up to 'L->top - 1'. */ const luaV_concat = function(L, total) { assert(total >= 2); + do { + let top = L.top; + let n = 2; /* number of elements handled in this pass (at least 2) */ + let v = L.stack[top-2]; + let v2 = L.stack[top-1]; + + if (!(v.ttisstring() || v.ttisnumber()) || !tostring(L, top - 2)) // TODO: tostring + ltm.luaT_trybinTM(L, v, v2, top-2, TMS.TM_CONCAT); + else if (v2.ttisstring() && v2.value.length === 0) + tostring(L, top - 2) + else if (v.ttisstring() && v.value.length === 0) + L.stack[top - 2] = L.stack[top - 1]; + else { + /* at least two non-empty string values; get as many as possible */ + let tl = v.value.length; + /* collect total length and number of strings */ + for (n = 1; n < total && tostring(L, top - n - 1); n++) { + let l = L.stack[top - n - 1].value.length; + // TODO: string length overflow ? + tl += l; + } + + let ts = new TString(""); + for (let i = n; i > 0; i--) { + ts.value = `${ts.value}${L.stack[top - i].value}`; + } + + L.stack[top - n] = ts; + } + total -= n - 1; /* got 'n' strings to create 1 new */ + L.top -= n - 1; /* popped 'n' strings and pushed one */ + } while (total > 1); /* repeat until only 1 result left */ }; /* diff --git a/tests/lvm.js b/tests/lvm.js index d11eb9d..40a20bc 100644 --- a/tests/lvm.js +++ b/tests/lvm.js @@ -773,4 +773,26 @@ test('LEN', function (t) { 0, "Program output is correct" ); +}); + + +test('CONCAT', function (t) { + let luaCode = ` + return "hello " .. 2 .. " you" + `, L; + + t.plan(2); + + t.comment("Running following code: \n" + luaCode); + + t.doesNotThrow(function () { + L = getState(luaCode); + VM.luaV_execute(L); + }, "Program executed without errors"); + + t.strictEqual( + L.stack[L.top - 1].value, + "hello 2 you", + "Program output is correct" + ); });
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