begun argument underlining

3 files changed, 84 insertions, 4 deletions

diff --git a/src/server/analysis.odin b/src/server/analysis.odin
index cd505ce..d7ac8ef 100644
--- a/src/server/analysis.odin
+++ b/src/server/analysis.odin
@@ -57,6 +57,7 @@ DocumentPositionContext :: struct {
 	hint:             DocumentPositionContextHint,
 	global_lhs_stmt:  bool,
 	import_stmt:      ^ast.Import_Decl,
+	call_commas:      []int,
 }
 
 DocumentLocal :: struct {
@@ -2285,6 +2286,29 @@ get_document_symbols :: proc(document: ^Document) -> []DocumentSymbol {
 }
 
 /*
+	Parser gives ranges of expression, but not actually where the commas are placed.
+*/
+get_call_commas :: proc(position_context: ^DocumentPositionContext, document: ^Document) {
+
+	if position_context.call == nil {
+		return;
+	}
+
+	commas := make([dynamic]int, 0, 10, context.temp_allocator);
+
+	if call, ok := position_context.call.derived.(ast.Call_Expr); ok {
+		for i := call.open.offset; i < call.close.offset; i += 1 {
+
+			if document.text[i] == ',' {
+				append(&commas, i);
+			}
+		}
+	}
+
+	position_context.call_commas = commas[:];
+}
+
+/*
 	Figure out what exactly is at the given position and whether it is in a function, struct, etc.
 */
 get_document_position_context :: proc(document: ^Document, position: common.Position, hint: DocumentPositionContextHint) -> (DocumentPositionContext, bool) {
@@ -2357,6 +2381,10 @@ get_document_position_context :: proc(document: ^Document, position: common.Posi
 		fallback_position_context_signature(document, position, &position_context);
 	}
 
+	if hint == .SignatureHelp {
+		get_call_commas(&position_context, document);
+	}
+
 	return position_context, true;
 }
 
diff --git a/src/server/signature.odin b/src/server/signature.odin
index 883bd2e..64028c8 100644
--- a/src/server/signature.odin
+++ b/src/server/signature.odin
@@ -16,7 +16,36 @@ import "core:slice"
 import "shared:common"
 import "shared:index"
 
-
+SignatureInformationCapabilities :: struct {
+	parameterInformation: ParameterInformationCapabilities,
+}
+
+SignatureHelpClientCapabilities :: struct {
+	dynamicRegistration:  bool,
+	signatureInformation: SignatureInformationCapabilities,
+	contextSupport:       bool,
+}
+
+SignatureHelpOptions :: struct {
+	triggerCharacters:   []string,
+	retriggerCharacters: []string,
+}
+
+SignatureHelp :: struct {
+	signatures:      []SignatureInformation,
+	activeSignature: int,
+	activeParameter: int,
+}
+
+SignatureInformation :: struct {
+	label:         string,
+	documentation: string,
+	parameters:    []ParameterInformation,
+}
+
+ParameterInformation :: struct {
+	label: string,
+}
 
 get_signature_information :: proc(document: ^Document, position: common.Position) -> (SignatureHelp, bool) {
 
@@ -40,15 +69,30 @@ get_signature_information :: proc(document: ^Document, position: common.Position
 		get_locals(document.ast, position_context.function, &ast_context, &position_context);
 	}
 
+	for comma, i in position_context.call_commas {
+		if position_context.position > comma {
+			signature_help.activeParameter = i+1;
+		} else if position_context.position == comma {
+			signature_help.activeParameter = i;
+		}
+	}
+
 	call: index.Symbol;
 	call, ok = resolve_type_expression(&ast_context, position_context.call);
 
 	signature_information := make([dynamic]SignatureInformation, context.temp_allocator);
 
-	if _, ok := call.value.(index.SymbolProcedureValue); ok {
+	if value, ok := call.value.(index.SymbolProcedureValue); ok {
+		parameters := make([]ParameterInformation, len(value.arg_types), context.temp_allocator);
+
+		for arg, i in value.arg_types {
+			parameters[i].label = common.get_ast_node_string(arg, document.ast.src);
+		}
+
 		info := SignatureInformation {
 			label = concatenate_symbols_information(&ast_context, call, false),
 			documentation = call.doc,
+			parameters = parameters,
 		};	
 		append(&signature_information, info);
 	} else if value, ok := call.value.(index.SymbolAggregateValue); ok {
@@ -62,8 +106,6 @@ get_signature_information :: proc(document: ^Document, position: common.Position
 	}
 
 	signature_help.signatures = signature_information[:];
-	signature_help.activeSignature = 0;
-	signature_help.activeParameter = 0;
 
 	return signature_help, true;
 }
\ No newline at end of file
diff --git a/src/testing/testing.odin b/src/testing/testing.odin
index e74fb0e..7b30e93 100644
--- a/src/testing/testing.odin
+++ b/src/testing/testing.odin
@@ -145,6 +145,16 @@ expect_signature_labels :: proc(t: ^testing.T, src: ^Source, expect_labels: []st
 
 }
 
+expect_signature_parameter_position :: proc(t: ^testing.T, src: ^Source, position: int) {
+	setup(src);
+
+	help, ok := server.get_signature_information(src.document, src.position);
+
+	if help.activeParameter != position {
+		testing.errorf(t, "expected parameter position %v, but received %v", position, help.activeParameter);
+	}
+}
+
 expect_completion_details :: proc(t: ^testing.T, src: ^Source, trigger_character: string, expect_details: []string) {
 	setup(src);